There's a surprising amount of junk installed on your hard drive right now, just by the applications that you're using.
This valuable space can be recovered however using Trimmit! which aims to delete junk files, clear resource forks, strip universal binaries, clean out NIBs, strip debug symbols, compress TIFFs and remove foreign languages. It does with this a touch of humor too asking you only to "Drop your fat app in here. Gently" in the simple interface. Just drag your application that you want to trim from you applications folder and it will bring up a dialog indicating what you can remove.
Then click "Trimmit!" and you'll be presented with a Terminal dialog displaying the results. This doesn't really mean much and it would be more useful to know exactly how much disk space you've freed but you have to take Trimmit! at its word that it has trimmed off unnecessary files. It does make a backup copy too so if anything goes wrong, you can reverse it. Where it stores this backup is not clear - you would think that backing up the application would consume even more diskspace but obviously not.
Use Trimmit! with care however. Some users have reported that it has affected applications so that they don't open anymore so always make a backup.
Trimmit! is an excellent application for anyone that doesn't want to pay for a trimmer like Xslimmer, but wants to do away with bloated applications.