if you want a scrabble dictionary using the scrabble players dictionary (8 letter words or less, nothing dirty) there is one at the scrabble website.
http://www.hasbro.com/scrabble/en_US/search.cfmhonestly I have never tried to use it with the included browser, but it works with opera mini beta and bolt, I prefer to use opera mini beta over bolt for the scrabble dictionary.
If you just want a list of all legal words, includes dirty and longer words I cam across this webpage
http://www-personal.umich.edu/~nicholsa/scr/owl2.htmlagain, I have not used it in the pre-installed browser, and it isn't overly convenient to use (in number of letter order, so all 2 letter words, then 3, then 4).
BTW, if you haven't already DLed one of the non-ATT browsers that should be one of your first priorities.