First about OP, only information that i heard about TM going to offer N900 is from representative at Costco Wireless, when i asked TM stores reps, they told that they did not hears about this one at all or they did not heard about this phone will be offered through TM.

About the data plans. I myself have $9.99 plan (not current, but the old one, Tzones Pro), that is giving you unlimited Internet access, 100 pic msges (that are no use because no MMS), and 300 text messages. It is why I'm buying unlock phones, and do not want to switch to any TM data phones.

Recently TM started to offer:

Unlimited Web for phones Free Trial: This service is recommended for frequent Internet users who regularly access the mobile Web to browse their favorite Websites, search for music and videos, etc

They are offered it through the phone or through you personal TM online account, when you got to upgrade you services. I tried to find out for about that that "Free Trial" mean, but all what i got back is that just a name, and for now it was offered for several month.

If you have a data phone listed in ur TM account and $9.99 plan is not available, it is a easy work around to make it available. Basically, just switch you phone to some other one, like Sony TM506, and then add a new data plan, you might need to wait up to 5 working days to change take an effect before it become available.