Drewman,
The frame rate and video formats you are able to acquire in LabVIEW will be entirely based on your camera. A USB camera must be Direct Show compatible to work with the IMAQ drivers. Some USB cameras are fully Direct Show compatible and offer multiple video formats and frame rates. Others only provide a single format / frame rate that is direct show compliant and others that are only accessible with the camera manufacturer's software.
As for converting a color image to Grayscale the following article and example describe that process:
IMAQ: Color Image to Grayscale
http://decibel.ni.com/content/docs/DOC-5003
How Do I Convert a Color Image to Grayscale?
http://digital.ni.com/public.nsf/allkb/ED42C55C29B9B34C862570A60079952E
As for using a timed loop to adjust the frame rate I highly recommend you not use the Timed Loop in a non-real time development environment like Windows. The Timed Loop is designed for use on Real Time operating systems and while it will not generate an error when used in windows it will not function as you might expect. You can, however, use a while loop with a Wait (ms) delay in it, but keep in mind that this will only be accurate to around 1 ms and you cannot gaurantee a fixed frame rate (one time your loop may take 5 ms, the next 10, the next 1. It all depends on what windows is up to in the mean time).
Please let us know if there is anything else we can do for you.
Regards,
Sam K
Applications Engineer
National Instruments
