site hacked

we running latest wp 3.2.1

with latest plugins

akismet 2.5.3
audio player 2.0.4.1
capability manager 1.3.2
cbnet twitter widget 1.1
cforms 11.7.1
flash mp3 player 10.1.5
gigpress 2.1.14
nexgen gallery 1.9.0
tubepress 2.2.9
wp e-commerce 3.8.7.2

the site has been compromised 4 times in the last month each time we have changed the passwords & restored from a clean back up & upgraded everything to ensure we are running the latest versions but continue to have problems. Yesterday it appears to be running a phishing scam for nedbank.