V-Window - Provides window control for plug-ins, surround panners, and any other windows.
MultiPanel - New multi-purpose view for a better organized GUI.
Additional DAW Support - Live, Reason, Reaper, Studio One, FL Studio, Tracktion.
Logic Improvements - Instrument parameter editing, counter jog/scrub control.
Pro Tools Improvements - Full-screen surround panner control. Sticky modifier buttons.

I use Cubase 6 and especially the V-window feature is fantastic - every window I have open in Cubase, I can select on my iPad and tweak the controls by hand. Just slightly laggy but I'm not on an ad-hoc network, still works really well.
These are actual screenshots from my iPad:




Have only used it very briefly but everything seems to work as it should. It's not cheap, $49.99, but for what it does it's definitely worth it. There's a free version to try out as well.
For me, this is what I've been longing for ever since I got an iPad.
More info at Neyrinck website:
http://www.neyrinck.com/en/products/v-control-pro