--First Post--
1) Mac OS X runs the UNIX version of chkdsk (scandisk) at startup. Also it does other checks at startup.
2) You can get Norton Utilities or System Works for Mac, and they work well, however I would stay away from System works untill at least verison 3, because it has some problems with OS X 10.2 file permissions.
3) On your System Install (when you boot from it) You can use the Application Manu to launch Apple's Disk First Aid. From there you can repair Permissions (Which can be courpted due to large numbers installations and deinstallations), also you may scan and repair most HD problems from there.
4) To Uninstall, 3 things may work, depending on who wrote the program, and which method they use to install.
a) Run the Installation Program Again, there will be an option to uninstall.
b) Run the included Uninstall application.
c) Delete the Folder containing the software (This will just remove the software, not the preferences like the other two will.)
Any more queries or questions feel free to ask. Thats what we are all here for.
TEG