I need someone to find some webinar (web conferencing) software.

Features the software will need:
- Screen sharing
- mac and PC
- Recording (audio and video)
- There are a few other features I want (will explain when you're selected)

Information I'll need:
- cost per month
- how many users
- how many presenters
- how users interact with software

There are many webinar software packages on the Internet, You'll need to sort through them and find the top 10 (based on the criteria I specify) and provide a spreadsheet comparing the features.