If you want Words With Friends for windows phone, try Wordament
Words With Friends is a popular game by zygna on iPhone and Android. And we donot have news on when they will release a windows phone 7 version. But for samsung focus users, there is one game you can just try and I am sure that you will love it. The game is Wordament.
Wordament is release at 04/01/11. Almost everyone likes it and it is 5 stars with about 100 reviews!
Wordament is a unique kind of word game—a word tournament—where you are competing with the whole internet to be the best word searcher in every game. Every player is competing on the same board, in real time, to get the highest score. Will you be the Wordament champion?
It is FREE.
Another Words With Friends substitute, http://www.samsungfocusapps.com/words-by-post-free-for-samsung-focus-substitute-words-with-friends-for-windows-phone/