The previously posted info on flies is pretty good. Generally, you want sand eel
and silverside patterns in various sizes. I've had better luck with smaller sizes
(size 4-6) for albies, with white my most productive color.
For guides, you can also check with Coop's Bait and Tackle in Edgartown. Cooper
Gilkes (Coop) is an outstanding flyrodder and guide, and will sometimes guide
waded trips. Jamie Boyle is another successful guide and flyrodder; I think he's
reachable through Coop's. Personally, I usually call Coop's the week before I go
for my annual trips. They are pretty good about advising me on flies that have been hot
recently, so I can tie up a few if I don't have some in stock. Good luck!