Well, I cannot suggest any INTERNATIONAL web site
sorry.
I bought it here, Korea, but you can search about those films at ebay or somewhere - Japanese film makers still make those unreflective films for cell phones and PDAs (and you can also find some interesting films like 'private' filter
Buy one of those for 3.5' screen.
Not so popular item, but there would be. (in Korea, imported(japanese) unreflective 3.5' films for PDA are around $10 or $15. Might a bit more expensive, I'm not sure though)
For the 'dust-free' protect film, remember that the some 'humiidty' never hurt GP2x
I once read a guy in here used his 'bathroom after taking shower' for that task, that's one way.
I usually drop couples of droplets of water ON the LCD and try to stick my film on it. With water, it is very easy to stick and remove without any air-ball nor dust. (If you failed once, you can always try again with adding more water. Just finish it by removing waters from under the film with tissue or towel.
Of course, be careful no water into the machine, but I never failed even with my laptop (with private filter, though) Actually I always use the water-wased film (water-remaining) It probably is not so sticky atm but it will be again after water gone.
I hope you guys good luck