Nokia Lumia 900 or HTC X310E Titan

Does anyone know if I could use the Nokia Lumia 900 or HTC X310E Titan as a wifi only device? I want to purchase one but use is without any cell service as a wifi only device, like the ipod touch?

Update: Thanks for the replies. I just want to make sure before I go and purchase one. I am leaning more towards HTC X310E Titan, as I can get a good used one for a pretty good price.
I just want something Microsoft to compete with the Ipod.
One more question, Would I have full access to the marketplace as well as the new 7.8 update that is coming out