Tiamat has just been updated. Included in this update is one of the most request features, multi tile selection. Now by holding the ctrl or shift key, you can add tiles to your selection. Thus you can move, cut, and paste larger sections of your map. I created a video that demonstrates this new feature:

In addition, I changed the tile placement icon from a blue box to the tile(s) currently selected. Those tiles should standout from the other tiles on the map as they are slightly transparent (except on IE).

I think there will be 1 or 2 more updates before I drop the Beta tag to Tiamat. I'll blog about the ramifications of that in the not too distant future.

Also, remember, I'm still running the Tiamat Map Building Contents until December 1st.