Video Conferencing through a VPN tunnel

[WVGrandpa]

Hello all, I am posting here in hopes of finding suggestions on Video Conferencing through an IPSEC VPN Tunnel, this tunnel is established and working as we have the need to have access to information at the other office. We have 2 offices at present about 40 miles apart. The owner wants to be able to do video conferencing between the offices as well as between field people and owner if he is not in the office. I understand that when out on the road products like Skype, ooVoo are needed these have already been looked at as possible solutions. With the video conferencing we need the ability see the other person screen at times to show problems and information that need checked. We can have several persons on the same conference call at the same time.

My budget is not large for this project so cost is a factor.

Any help would be greatly appreciated.