jusy wanted to let you know that the intrusion you speak of is not alway ultrapeer. I have never been connected as an ultra peer and am constantly having attempts made on my computer in limewire.
Unfortunately the site is becoming crowded with virus and trojans and hackers.
Get the best anti-virus you can find.
get a trijan detector, get zone alarm, get whatever you need to protact yourself.
Filesharing is so much fun, but very risky.