I was considering buying a controller with moving faders to write automation to my tracks - eg Behringer X touch or some such like. But then I wondered if anyone uses an app to do this via wifi or something?
I have tried searching using various variations of terminology, but all I seem to find are apps that let you knock out a tune ON your ipad.
Does anyone use or know of an app that could be used as a controller for Sonar X3e so that I could automate mixes?
If not, then it will be a hardware controller, I guess....
 
Thanks for any suggestions.

Just bought Korg Nanokontrol for the same purpose...Would love to have an app for it. I will keep an on this thread... thanks for bringing up this topic...

Do a quick google for 'mackie control ipad app'.  It took me to this site: http://appcrawlr.com/ios-apps/best-apps-mackie-control
I tried V-Control a few years back (I believe there was a free light version available). It worked quite well, but I personally don't like mixing with a touchscreen. 
 
You should also check out Lemur and/or TouchOSC. They both let you design your own controllers. 
I use Lemur myself and there are a lot of (user)templates available already, including a sonar template (If I remember correctly) 
 
 

V-Control Pro works pretty well for me. Only downside is you need to disable gestures in iOS while using it. Otherwise, for example, raising four faders at the same time is interpreted by iOS as a "four finger up-swipe" and dumps you into the screen that shows all open apps.

It doesn't integrate with Sonar quite as well as Apple's Remote does with Logic, but for a third party generic controller it's pretty good. Better than my Nano Kontrol in my opinion, because controllers in the app follow the controller settings in Sonar so there's no "control chasing" involved.

One disadvantage to it might be that it uses your LAN to connect with Sonar. So if your PC has a wi-fi card that causes a lot of dpc latency and has to be disabled to get low latencies in Sonar there might be an issue there. My DAW PC has wired networking, so it's not a problem for me. Connections using bluetooth usually suffer quite a bit of latency and can cause the same sort of problems as wi-fi adaptors.

I've got all sort of those apps for iPad. After a while when the coolness of doing that wears off you are back to pre Ipad production.

I bought the full version of V Control from Neyrinck over a year ago, and I've been very happy. I can record and navigate from different places in my studio, and I can leave my FaderPort on my desk.

They just upgraded to V Control Pro 2 for the driver that runs on your PC, and V Console for the iPad and other-device app. It took me a lot of work to get VCP2 to work with the existing iPad V Control app, but now it works great (let me know if you have any questions).

V Console isn't working for SONAR yet, but the current app is just fine. The new one will run from Android and iOS phones, multiple devices, etc.

Many thanks to people who took the trouble to post. Much appreciated.

+1 for V-Control (not an official endorsement, a personal one)

When if ever are cakewalk going to create an iPad app for remote control. It seems just about every other daw is onboard.

Splashtop. Outstanding. http://www.splashtop.com/