In modconf install:
videodev (This is also known as the "video4linux" or "v4l" module)
usbcore Install on all systems usb-uhci This is needed to enable USB circuitry on the motherboard so it's (Intel) system-specific. If you get errors trying to install it, try the usb-ohci or uhci drivers. ibmcam USB IBM (Xirlink) C-It Camera support. If you have another cam try the ov511 module (OV511 is a chipset that some cams, like the Creative WebCam III, are built on) or the dc2xx for those Kodak models.
You could also try both the cpia and cpia_usb drivers (both at the same time). These are under the misc category instead of the usb category and some cameras (Creative WebCam II for example) will work with these. (There's also a cpia_pp driver for parallel port camera models but be sure to also use the cpia module with it.) The c-qcam and bw-qcam modules under this category are for the parallel port QuickCam cams. A list of cameras and the drivers they use are given in Section 4 of the WebCam HOWTO at the LDP (Linux Documentation Project).