Linphone supports video calls on IOS !
We just published on the Apple store a new release of Linphone for IOS that supports video calls.
Supported video codecs are VP8 (WEBM), H264 and mpeg4. Supported resolution is QVGA (320x240) at 12 fps.
This works on phones models using an ARMv7 processor with NEON instruction set (iPhone 3GS, iPhone 4/4S, iPad) starting from IOS 4.x. IOS 3.x is still supported but for audio only.
This new release also introduce some nice features like, SILK (Skype codec), multi calls and audio conferencing.