In the past none of our VSIP partners cared much for getting the VSIP SDK to match a release of a CTP (Community Tech Preview). If you're a VSIP partner, I'd like to hear from you about whether you are going to try to get your integration working on the June 2005 CTP for VS2005 or not. If you are, you may need the corresponding VSIP SDK. Please let me know if that is the case. Just comment to this post and I'll let you know what we decide regarding providing it to you.