P2Pool wallet address vs public key ?

[mmininginc]

We all know the standard usage of a p2pool node is to use your address as the user...
If you take a look at p2pool.org, then you'll see that for some coins p2pool.org tells you to use a public key instead of a wallet address.
I'm a bit confused... is this another name for your wallet address, or are we talking about something else, and if so... where do I get my public key?
Tnx.

[mmininginc]

Never mind... I found out it's not the same:
http://brainwallet.org/#generator