QUOTE(Morgan's Munchkin @ Oct 27 2006, 11:52 AM)

Pachebels Canon.
Try doing a search for it on Sibeliusmusic.com - I think they do a free printable version of it for violin and cello.
Edit: Sorry - Didn't see you wanted collections. Have you looked at Handel's 4 sonatas for treble recorder and basso continuo. They are meant to be for recorder but are on the grade 5 flute list and also work on violin, and the bass part is written for cello (there's a piano part as well, but it would probably work without it).
Good suggestions. There is also a book available of Handel duets arranged for violin and cello - Katyjay played one of them with Supea at the recent Adult learners concert. I can't think of the title of the publication, but if you sent a PM to Katyjay I'm sure she would oblige with the information. I will point out that not all of them are easy duets, some are actually quite difficult and will need a higher skill level before tackling them.
Generally speaking, lower level duets for violin and cello are thin on the ground, especially as collections. Plenty at the upper end of the learning curve - some terrific duos by Beethoven for example.