revoking a UID

[Jason Markley]

When one revokes a UID to effectivly change addresses, how does that 
affect the signatures that were on the key?


In other words...

1. Generate a key with uid1.
2. Get this key signed by your friends, etc.
3. Generate a new uid, uid2.
4. revoke the old uid, uid1.

Will your friends that signed your key origionally still see your key as 
valid?  Will they have to sign the new uid in order to have your key be 
valid again?  What are the security implications of having your friends 
still see your key as valid when you've revoked the uid that they signed?

Thoughts are much appreciated.

-Jason