Windows Phone 7 may have its rough edges (no multitasking, no copy and paste), but it does appear to have a number of relatively enthusiastic hardware partners.  And now AT&T has revealed itself as a key ally with some big claims.

A spokeswoman for AT&T, the second largest mobile phone carrier in the U.S., told PC World, "We'll be the premier carrier for Windows Phone 7.  We haven't given guidance on timing."

Altimeter Group analyst Michael Gartenberg claimed in a Twitter post last week that AT&T has plans to buy 8 million Windows Phone 7 smartphones.  That's a fair number, but still very plausible considering that globally 55 million smart phones were sold in Q1 2010.

There's no telling yet what exactly AT&T means by being the "premier" carrier of the new Microsoft smart phones.  It could simply be alluding to the company's data network, which is generally regarded as superior to that of America's top carrier, Verizon.  Or it could even be suggesting something more exciting.

Regardless, Microsoft likely is more willing to work with AT&T after Verizon's involvement in the trainwreck that was Microsoft Kin.  While the failure of Kin rests mostly on Microsoft's shoulders, Verizon deserves a bit of blame as well -- it could have offered more competitive pricing and advertised it more effectively.

In the wake of Kin and questions about Windows Phone 7, AT&T seems like the only one enthusiastic about Microsoft's upcoming phone platform.  Sprint and Verizon reportedly refused comment on the platform and T-Mobile never responded to a request for comment.

For AT&T, regardless of how Windows Phone 7 is received Windows Phone 7 could play a key role to drawing in more customers.  AT&T has always prided itself for having a diverse portfolio of smartphones.  While its Android offerings have been a bit lacking, it has, of course, the infamous iPhone.  And its spokesperson recently bragged to us that the company has "more smartphones than any other U.S. carrier."

Thus Windows Phone 7 products, like the Dell Lightning, should form a critical fourth pillar to AT&T's efforts, which currently consist mostly of Apple, Blackberry, and Android smartphones.