www.familiesagainstfees.co.uk/
is the website for Families Against Fees, set up by radio presenter Liz Kershaw with the backing of the NUS. More about the fledging organisation on the NUS site and I think there's a facebook page.
If you go on the site, you can customise a letter to your MP which is then emailed to him/her ahead of next Thursday's tuition fees vote.
Just done it myself - one small voice but they will stack up.