Hello Chris,
(sorry my english)
I don't know, Want You make free vision toolkit, yet? I found project on internet - Robolab for Labview. This is project use the capture cards, webcams and other directshow devices under Windows XP - via interface of QuickTime. I tried Vi-s, working. I set resolution and others parameters from program and I snap pictures.
I interested in this free solution, it's fine idea.
OpenVisionToolKit go, go, go ...