Can I delete xcode, classic etc and reinstall?

Quick question, in my installers folder I have XCODE tools taking up like 600mb, plus some classic apps and stuff. Can I delete these and install later? When I put in my powerbook CD it just has "Install OS X" on it. If I remove these "install xtools" from my HD is it possible to install them later if I need it, same with the classic apps or should I leave it? Or install xcode and then remove?

XCode and Classic should be on one or another of your install disks...sometimes on the system restore disk, and sometimes on another Applications disk. Either way, you shouldn't have a problem re-installing them so long as you kept your original disks. Apple always gives you full backups of whatever software your system shipped with.