[liam_ja]

https://en.bitcoin.it/wiki/Wallet_encryption

It would be pretty unfeasible to attempt a brute-force, due to the number of encryption rounds.

[1337biz]

I usually use a similar pattern for my passwords. That way I could probably generate a few hundred combinations and run the list against the wallet. Would of cause be easier if there were a tool for doing that.

[Anderkent]

There is a service! http://www.walletrecoveryservices.com/