The fact that your problem comes and goes may be a symptom of an intermittent hardware problem.
Cracked, loose, or improperly soldered internal connections can cause the sort of unexpected failure followed by unexpected return of proper function that you report. Although you may have corrected the problem now, if you have an intermittent hardware issue, vibration, even that from normal use, or changes in operating temperature can cause reoccurrence.
If the problem continues, expect that you may have an intermittent hardware problem. If the problem is sufficiently annoying, ask your Apple-Authorized Service Provider to check out your symptoms.
Because such problems are not reliably repeatable, they can be difficult to find, so make a backup and expect to leave your Mac with the AASP for a while. However, once found, your Apple service provider can usually correct the problem quickly.
If you want to try one more thing on your own first, use your Mac's Disk Utility to repair permissions. Then download and apply the latest Combo Update for your OS. Currently, the latest Leopard Combo is here: http://support.apple.com/kb/DL866. Repair permissions again immediately following the system restart that completes the Combo update.
Properly applying the Combo version of updates can sometimes correct software problems. However, if your trouble is caused by a hardware problem, you'll need the help of your AASP. There are no user serviceable parts of iSight.