We did a package through the website i mentioned above and stayed at the St GIles hotel in feltham, 4 miles away from Heathrow. It was a really nice room, clean and pretty and spacious, and we got 3 weeks of parking with it - all for 120 pounds! the 3rd week of parking was extra, but all we had to do was call them and pay a few extra pounds.
we will definitely go to that hotel again the next time we fly. they had a shuttle that goes to the airports, but not the international terminal (most hotels didnt, theyd take you to terminal 1 2 or 3 and then you have to take another bus to terminal 4) - - so we took a cab. easy as can be - good hotel - great deal, would do it again!