While it only affects a few functions now, like AirDrop, your Apple ID will be even more important when iCloud is available. To set your Apple ID in Lion (provided you have one), go to System Preferences and click on Users & Groups. There you will see your login information plus a button to set your Apple ID. If you don't already have an Apple ID or want to learn more about it, check out Apple's page on it here.

This article was originally published on Tuaw.
A few nasty gotchas in Lion