It works!
I have Zoneminder working with my Logitech Quickcam Pro 9000 webcam and it's displaying a good quality picture and detecting events. Unlike some other webcams I've tried, it works well in low light or in full daylight.
It was all relatively easy once I'd overcome a few hurdles and the odd bit of misleading information... I spent ages trying to get xawtv working with my webcam because the documentation implies that a working xawtv is a pre-requisite for a working Zoneminder. Not true! I couldn't get xawtv to work at all. I may have misunderstood something here, so please correct me if I'm wrong, but a working xawtv is irrelevant if you use a v4l2 device and therefore have to use mjpg_streamer. Until v4l2 is natively supported in a future release of Zoneminder, using something like mjpg_streamer is the only option.
Once I'd understood that and been pointed towards using the correct url to view the output
http://localhost:8080/?action=stream then I could see it was working. From there, setting up a basic working configuration in Zoneminder was relatively easy.
I nearly gave up a couple of times. It's taken me several days of searching and reading, getting an understanding of the vagaries of uvc, v4l, v4l2, etc. Only then could I be reasonably confident that the webcam I had bought would work.
This is a useful document on linux supported uvc devices:-
http://linux-uvc.berlios.de/#devices
This document (and the Excel/PDF document it refers to) is useful if you are considering a Logitech webcam.:-
http://www.quickcamteam.net/hcl/linux/logitech-webcams
In the case of the Pro 9000 it turns out that there are
lots of sub-models some of which have bugs while some are problem-free. Fortunately the part number of mine (the part number is
only printed on the paper tag that's attached to the cable near the usb connector) showed mine to be one of the problem-free sub-models - a 861-464-0000.