> Is using a GUID a good idea?

We use GUIDs for our product. This way if someone has multiple sites,
remote laptop users that synchronize data, etc. and data from multiple
places needs to be merged into one database, you don't have ID
collisions since they are globally unique IDs. We convert the GUID to
strip out the dashes and compress it using a base-36 (A-Z, 0-9)
conversion on it so it isn't quite as long. It's still a farily long
string, but you shouldn't ever have to worry about two people anywhere
having the same ID.

David R.