Android lands at T-Mobile Tuesday, and as part of the effort to deliver the Google phone to the mobile market, T-Mobile is considering including free e-mail access.

The new Android-powered phone will have Google’s (GOOG) Gmail service built in, and T-Mobile executives are considering offering access to Gmail free, without the need for a data plan, says one person close to the discussions.

The HTC-manufactured T-Mobile phone will be the first of the hotly-anticipated Android-operated handsets, and one of several new challengers to Apple’s (AAPL) iPhone. The Android project was created by Google to cultivate an open application platform to operate next-generation mobile phones.  T-Mobile  – a unit of Deutshe Telekom (DT) – is expected to unveil the phone during a press conference at 10:30 ET Tuesday, and offer it for sale later this fall.

Analysts see the Google phone as the beginning of an important lead in mobile Internet advertising through ads appearing on Android powered phones. Sandeep Aggarwal, an analyst with Collins Stewart, estimates that the phone will generate $5 billion in incremental revenue for Google by 2011.

Should T-Mobile decide to offer free Gmail access, it would be seen as a big counter move to Research in Motion’s (RIMM) BlackBerry e-mail service, which costs $15 a month extra. And if telcos embrace Google’s ad-supported free e-mail, it could help drive Google’s ultimate aim to spread its successful desktop advertising business to mobile phones.

The move to provide free Gmail has risks, however.

T-Mobile could undercut its own data revenue stream from BlackBerry subscribers if users trade in their Curves and Pearls for the Android phone. But T-Mobile, the No.4 wireless shop, needs an attention-getting strategy like free e-mail to help set itself apart from bigger players like AT&T (T), Verizon (VZ) and Sprint (S).  

Google referred calls for comment to T-Mobile and a T-Mobile representative could not provide an immediate comment.

As for the HTC Android phone itself, one user who got an early trial described the slide out keyboard as a little awkward for some typing tasks. The browsing quality however was “better than BlackBerry and close to the iPhone.”