There are a lot of applications out here, like different languages, compilers, and utilities, but for everyday XCode development I found these to be very handy.

MD5.app allows MD5 hashes to be easily generated for downloaded files by simply dragging and dropping the file onto the application. The hash is shown on the screen to allow easy visual validation helping to make corrupt downloads a thing of the past.

SvnX is an open source GUI for most features of the svn client binary.

FScript is a set of open source tools that complement Xcode and Interface Builder. Interactive introspection, manipulation and scripting of Cocoa objects.

SQLite Database Browser is a freeware, public domain, open source visual tool used to create, design and edit database files compatible with SQLite.

FreeDMG can make internet enabled disk images for distribution to Macs as well as ISO/Joliet hybrid images for cross-platform delivery.

Hexfiend is a fast and clever open source hex editor for Mac OS X.

Visual Paradigm for UML 7.2 Community Edition is a super powerful and feature packed charting and diagramming tool.

ClipMenu can manage clipboard history. You can record 8 clipboard types, from plain text to image.

Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.

Silverskin is designed to allow web developers, who deal with many projects at once, quick access to FTP, hosting accounts, domain name accounts and more. Especially when dealing with off-site shared hosting, keeping track of usernames and passwords can be daunting.

Hope these free tools help you in your everyday programming, have fun!