Hej,
If you are in Englad, you could get it from http://www.elfa.se , they sell over the net and accept credit card. Also Farnell and Digikey may have it, but I haven't searched there.
The datasheet is available in our web repository:
http://webzone.k3.mah.se/projects/arduino-workshop/upload/default.asp?folder=28
/David