FreeBSD doesn't have any serious drivers for USB cameras. The only way to get video stream into FreeBSD box is via bktr driver and compatible devices or via web-cam (LAN connection). In both cases you will have the problem of making Skype aware of the devices.
OpenBSD and NetBSD do support UVC complaint USB cameras (essentially anything Vista ready). Ekiga works with video on OpenBSD but Linux compatibility layer can not emulate linux audio
so you can not use for VoIP. On NetBSD the latest supported version of Skype is 1.4 (last OSS version for Linux) which didn't have video. Ekiga works with video. I am not sure if NetBSD are working on ALSA support (I doubted as they have so many serious projects going on right now) in their Linux emulator layer which is necessary for Skype 2.0.