PeerBlock -
http://www.peerblock.com/PeerBlock lets you control who your computer "talks to" on the Internet. By selecting appropriate lists of "known bad" computers, you can block communication with advertising or spyware oriented servers, computers monitoring your p2p activities, computers which have been "hacked", even entire countries! They can't get in to your computer, and your computer won't try to send them anything either.
This is a continuation project for PeerGuardian ! We probably don't want block certain lists, such as Educational etc., but this can help to reduce any hacker and scammer activity towards the Bitcoin networks valid nodes and help to protect our wallets

I also started thinking about how Bitcoin 'service' providers might go about verifying new business whilst remaining anonymous. We can use P2P VPN applications to communicate and, for example, verify that a new contact actually has 10,000 Bitcoins to buy/sell by viewing the Bitcoin App. on their desktop !

Wippien -
http://www.wippien.com/ - Open source p2p VPN software.
Comodo Easy VPN -
http://easy-vpn.comodo.com/More suggestions to follow...