The excellent LotusLive Meetings app has been available for the iPhone/iPod Touch for a year or so now, but has just been released for the iPad as well:
I’ve already used it for 4 or 5 meetings and it is now my preferred access point – continue to get work done on the laptop whilst conference calls are running on the iPad alongside. Love it!
(A couple of minor feedback points for those behind the app. It would be better to have landscape-mode screenshots in the App Store, much more impressive. Also, one universal app that does iPhone and iPad would work better for many folks as there is no need to download and manage two different apps.)