Here are some links to actions, either online or by snail mail (which I still think of as real mail!)
The first is Church Action on Poverty, who have an e-postcard you can send to Patricia Hewitt (UK Secretary of State for Trade and Industry) asking for a legal limit to the amount of interest that can be charged on loans.
Then go add your face to Amnesty International's petition to control the arms trade.
Finally, write to your MP and tell them what was missing from the trade deal anonunced this week. The World Development Movement have a sample letter to print off.
See - it was easy!