In one of the PrPro fora, Dan Isaacs offered tips on workflow, when dealing with Camtasia and Camstudio footage. Here is the link to that article:
http://forums.adobe.com/message/2063028
His suggested workflow does utilize some other programs, both freeware and also from Adobe.
As the Techsmith CODEC's used can be very tricky directly into Premiere, some might find his article useful.
Hunt