Android and Me are trying to figure out when Android 2.0 will come to T-Mobile. As regards to the Motorola Cliq, this is what they found out:

We also asked about the Motorola Cliq which has begun shipping online and will be available in stores November 3, 2009. The Cliq features a custom version of Android dubbed Motoblur, which is based on Android 1.5. T-Mobile’s other two Android phones have already been updated to Android 1.6, so we were curious about their upgrade strategy for the Cliq.

The CLIQ ships with Android 1.5 software. We have no announcements at this time regarding new Android software updates. For more information about future updates to CLIQ and MOTOBLUR, it would be best to contact Motorola PR

I have yet to get an official response from Motorola PR, but I did some digging of my own. According to an inside source from Motorola, it appears Motoblur will be receiving an update based on Android 2.0 (and skip Android 1.6).