I have been experiencing similar problems:

found the following useful:

http://msdn.microsoft.com/en-us/library/ms176029.aspx

I'm still going through this. but its a long ardeous task. My tempdbs grew from 25gb to 33gb. But just bare in mind that it could be rebuilding of indexes over night thats the cause and in my case I suspect it is as the databases contains approx 200 GB of data.