You will find a ton of threads on Cape Cod fishing on
Fly Fishing Forum - SurfTalk
(hopefully above link won't get removed on this forum .. if it does PM me)
Many options depending on budget. Flats, surf, boat, kayak or canal. Stripers, blues or BFT (you got a 20wt?) .. but the funny fish won't be there in June.
You might think about a guide for one or two days .. you can probably hook up with someone on Surftalk if you are looking to share the cost.
If you know exactly where you'll be I might be able to find some more specific infos for you.
Generally expect to need 9wt or 10wt, intermediate and full sinker and ability to fish all hours night or day. 7wt or 8wt fine for short range, sight fishing for small to medium stripers. If you surf/flats fish, bring an inflatable PFD .. wouldn't want you catching the North Atlantic Drift back to Blighty without some added bouyancy!
Word of warning .. striper population has been in significant decline over last few years (please join Stripers Forever) .. who knows what 2011 will bring.