Songza 2.4 (free) - Songza 2.4 is an upgraded version of the music player for iPhone and iPod touch. Now available for the iPad as well, the app allows users to stream thousands of original playlists, and to share playlists via Facebook and Twitter. Additionally, the new version offers faster song loading and bug fixes. [Download - 25.7MB]

SketchBook Express 2.5 (free) - AutoDesk has introduced SketchBook Express 2.5, an update to its intuitive drawing application for iOS devices. Features of the upgrade range from a new Random Color option in the Color Editor to an integrated Palm Rest, and also include an enhanced toolbar and performance improvements. [Download - 35.3MB]

Noteshelf 6.0 ($6) - Noteshelf 6.0 works as a fully-featured, note-taking application designed for the iPad. It can be used to customize/organize notebooks, and includes handwriting-recognition technology. The latest update adds Retina Display compatibility, Smart Pen support, and various usability enhancements. [Download - 60.4MB]

My laboratory 1.2 ($1) - My laboratory is a new puzzle game for the iPhone/iPad, where players must colonize a planet by mixing and creating up to 200 different elements. The game offers both Game Center support and 19 achievements to unlock, as well as the ability to create everything from humans to sandy beaches. [Download - 6.6MB]

Track 8 2.0 ($2) - Ender Labs recently launched a new 2.0 version of its music playing and browsing tool for iPhone and iPad, labelled Track 8. In addition to now being a Universal app, the updated program includes AirPlay support, and allows users to now restrict downloading artist-image-backgrounds to Wi-Fi only. [Download - 16.3MB]