Many of the resources below are free or very low cost, and are sure to be useful to a lot of designers and developers out there.
As always, if we've missed something you think should have been included, please let us know in the comments. And if you have an app or other resource you'd like to see included next month, tweet it to @cameron_chapman for consideration.
Gridwax is a bookmarklet that lets you easily add an adjustable vertical baseline to any site right in your browser. Just install the bookmark, click on it, and then adjust the height with your arrow keys.
Chardin.js makes it simple to add overlay instructions to your apps via a jQuery plugin. It's easy to install and configure.
Photolettering is a free iOS app that lets you add text to photos you take within the app or images from your camera roll. It features some great fonts from House Industries, including Elephant, Kerpow, and Aztek.
Learn CSS Layout
Learn CSS Layout is a tutorial site that teaches you CSS layout techniques beyond the basics. It includes lessons on the box model, positioning, CSS frameworks, media queries, and much more.
UX Apprentice teaches you the principles of UX design with a layered approach, including discovery, strategy, and design. It includes information on the core principles of each layer, as well as real life examples and resources for each.
dsgnjbs aggregates the best design jobs from a variety of design websites, including Dribbble, Behance, Smashing Magazine, 37 Signals, and more.
Flat UI is a free web user interface kit that includes buttons, menu items, inputs, checkboxes and radio buttons, tooltips, and many more basic design elements.
FlatDesign is a showcase of designs with flat UIs. It includes everything from apps to portfolios to event sites.
TimeJump lets you add deep links to HTML5 audio and video content with a standardized API based on the YouTube deep-linking syntax.
SVG Patterns Gallery
The SVG Patterns Gallery is a collection of SVG patterns complete with code. SVG images are smaller than bitmap images generally, and stay sharp on high resolution displays.
Inkwell.io is a handmade sketch kit specifically for web and app designers that comes with all the tools you might want to sketching mockups and wireframes.
Flat+3D Mockup Kit
This Flat+3D Mockup Kit makes it easy to create attractive mockups for your apps on a wide variety of devices. There are free and paid kits included, depending on which devices you need.
Ivory is a simple, powerful, responsive front-end grid framework that easily scales from 1200px right down to 320px wide. It has a flexible layout with 12 fluid columns, is supported on the latest versions of all major modern browsers, and it's easy to use.
Mixture is a rapid prototyping and static site builder tool that works with your favorite editor. It supports various boilerplates, as well as support for creating your own.
Kippt lets you build an online library for collecting research, stories, inspiration, and notes. You can make your collections private or public, or just share them with specific people.
Photoset Grid is a jQuery plugin that lets you arrange images into a flexible grid, inspired by Tumblr's photoset feature. It was originally created for the Style Hatch Tumblr themes, but is now available for use outside of themes.
SuperBox is a jQuery plugin that works as a static image gallery that reveals the full size version when an image is clicked on.
jQuery Menu Aim
Want to create responsive mega dropdowns like Amazon's? jQuery Menu Aim helps make mega dropdowns more useful by anticipating the user's mouse movement to open submenus rather than delays and timeouts.
Retinise.js is a jQuery plugin that "retinizes" the inline images on your site using "data-src" instead of "src", so it only pulls the image you need rather than loading multiple versions.
Is a Follower
Mobify.js is an open source library that makes it easy to adapt your site for any device. It captures and manipulates your site's DOM before resources are downloaded, enabling resource control, conditional loading, and more.
Intro.js lets you add an easy step-by-step guide to introduce users to your site or app. It's fast and small, and offers both keyboard and mouse navigation.
Animatable lets you easily animate all sorts of properties, including background-color, background-position, border-width, font-size, color, border-radius, opacity, and much more.
Accounting.js is a JS library for number, money, and currency formatting. It even includes Excel-style column rendering for lining up symbols and decimals.
Bespoke.js is a DIY presentation micro-framework that offers a number of different slide animations, including coverflow, cube, and carousel, among others.
Soundtrack Volume ($34)
Soundtrack Volume is a handdrawn typeface that comes in two weights. It's a lively all-caps font with contextual alternates.
Press Style (free)
Press Style is a distressed sans serif display font. It has upper and lowercase letters, as well as a fairly large number of accents and symbols (especially for a free font).
Dottie Daze (free)
Dottie Daze is a handdrawn display font with dotted accents.
Futura FH Custom (free)
Futura FH Custom is based on Futura, with added accents, making it a great display font. It's free for personal and commercial use.
Langdon is a serious, dependable font that's free for personal and commercial use.
Cyclope is a distressed sans serif typeface that's free for personal use (commercial use requires a donation).
Defeated is a new display font with abstract letterforms that's free for personal and commercial use.
Benito is a proportional, geometric woodtype with six styles: print, stencil, and clean, each with italics.
Imperious is a funky geometric font that includes more than 450 ligatures.
Naive Inline ($20)
Naive Inline is a handwritten serif type family with three weights. It was a very Parisian feel, and allows for a ribbed or full bicolor interior.
Know of a new app or resource that should have been included but wasn't? Let us know in the comments!