I was in Arco recently (October 08) and found the guys at Vertical Sport (one of the many gear shops in Arco) extremely helpful. They also spoke excellent English.
Fabio Leoni I think is the owner of the store and FYI has equipped many of the routes there. He was pretty chuffed when we bought him a bunch of beers as a donation of sorts to his selfless bolting work at many of the cliffs there over many years. If you can find even a small amount to donate to him - one of the most prolific new routers it would be a great bit of karma.
FYI There are two English guides for the area from memory. One (the one we bought) is just for sport climbing, the other is for the huge (up to about 400m I think - maybe even longer) multi-pitch routes (some trad, some sport).
There is a very well set up camping area that is about 80-90% climbers (most of them from Germany when we were there). It wasn't particularly cheap but fantastic position - only a pleasant 5-10min walk into the town center and the gear shops. I'm sure you will find people to climb with over there - just ask around or post a note at the reception/small shop.