MacOS X Software

uControl - - GPL
allows you to remap capslock to control. also gives you the ability to do Fn+trackpad as a virtual scroll wheel function.

Monolingual -
free 600MB+ by deleting support for languages and input methods that you know you will never use.

StarfishX - - GPL
generates interesting background patterns.

ShadowKiller - - freeware
removes the shadows around windows, can speed up the interface.

Text Extras - - but it supposes to give all Cocoa-based apps emacs-like keybindings in input dialogs, and access to several internal features.

opensource screen savers - - open source
a bunch of screensavers. the SaveHollywood screen saver is interesting because it can display a flash animation or quicktime movie. which can be useful for product demonstrations or a mac-based kiosk.

Onyx - - freeware
lets you control many internal features (mostly gui features) of OSX.

Growl -
gives applications that support it a configurable way to provide alerts (instead of having bouncing icons in the dock)

FullScreen Player -
lets you watch quicktime movies full screen without buying the full version of quicktime ($12 shareware). you could probably spend a couple hours looking at the source to SaveHollywood screen saver and write your own thing that does the same.

TemperatureMonitor - - (shareware?)
watch the temp of your Mac. g3/g4 can only watch the harddrive temp. g5 has an on-die cpu temp and case temp as well.

Fink - debian-like package installer for various opensource apps.

Darwin ports -
freebsd-like package installer for various opensource apps.

MPlayerOSX - the #1 video player on Linux comes to OSX. With the interesting ability to play movies in place of the desktop wallpaper. Note that burried within the .app directory there is a normal mplayer binary that you can symlink to and use in the traditional Unix way.

divx codec for quicktime -

xvid codec for quicktime - - open source
a video codec for mpeg4

ffmpegx -
convert between video/audio formats

Mac OS X speed FAQ -

SharePoints -
allows much more customized control over the samba configuration in OSX. share directories other than Public/ folders

AquaLess -
less/more pager in a gui

XNMap -
nmap in cocoa. a bit more powerful than the "Port Scan" tab in NetworkUtility

zipdrop -
the best way to create ZIP files in OSX (opensource)

OSXvnc -
vnc server for OSX. this company sells an interesting gui testing product that uses vnc to test Mac, Windows, Linux, etc.

Freecell - - open source
finally the last reason to use MS Windows has been removed.

MacOS X Hints -
A hodgepodge collection of articles covering almost every issue you have ever had with your Macintosh.

wClock - - freeware
A nice simple menubar clock application that is substantially less braindead than Apple's.