NMR Database
Helpful to keep you on track when trying get your head round your chemical shifts. Has a graphical input so you can draw the molecule and get the shift.
Royal Society of Chemistry
Student membership is available very cheaply, and membership gives you discounts on various things, as well as a magazine, access to their on-line library and various other benefits.
(Updated by NP) You will need to get one of your tutors to sponsor you. Fee is currently £17 with discount for multiple years (max of 4years), so worthwhile to join up for last portion of your degree. They accept credit cards and cheques — I am awaiting response for alternative payment methods (eg Paypal, direct debit, etc), as I have neither. 🙂
Web Elements – Periodic Table
An online Periodic Table with lots of info about each element and its compounds.