This is some info on the new tenancy deposit schemes...
http://www.direct.gov.uk/en/TenancyDeposit/ind ex.htm
This is a pretty good example...
http://www.swansea.gov.uk/media/word/a/9/Assur ed_Shorthold_Tenancy_Agreement.doc
Bear in mind anything else they should do and abide by though eg paying council tax, not having pets (or getting written permission first), visitors, periods unoccupied (eg for insurance purposes).
Make sure you know about all the up to date regulations eg gas, electrical and fire safety.
Also check any restrictions if you have a mortgage in place eg some do not allow letting to DSS.