My players are just about finished with Burnt Offerings, and have enjoyed the usage of my iPad as the battlemap. I've seen a few different applications of the iPad in this manner, but none of them really met my desires as a GM.
This is what I do:
I have Splashtop XDisplay on my iPad - this program allows you to use your iPad as a second display via your wireless network.
I have Adobe PhotoShop on my laptop, and with it have adjusted the maps included in the AP (PDFs), and enhanced their grids. Each map is a PSD, and within it I have layers for "Fog of War" across unseen rooms, and "token" layers for the PCs and NPCs.
I leave PhotoShop's tools and menus on my laptop screen, and drag the file over to my iPad display. A minor zoom-adjust allows it to fill the iPad's screen.
I am now able to dynamically adjust PC visibility - such as in dark areas, including the ability to add extra vision to characters with darkvision (via sight range rings around each PC). My players don't have to lean over/move around the table to adjust their character, all of that is done from my end. They just say where they want to move, and I move them. Having multiple cats, this has saved us a few times where we would have had tokens flying everywhere from a well-aimed kitty jump.
I can have all of my PDFs (I don't have all the books in physical copies) open and available to me, as well as various other web resources, while still controlling the display on the iPad remotely with my mouse and keyboard.
If you have PhotoShop - or probably anything that can view/manipulate PSD files - and an iPad you can do this. It's been really great for us.
I have the maps from the Glassworks to Thistletop Level 2 all made, and would be more than happy to upload them somewhere if people are interested in trying this method. I'll be continuing to produce maps as we continue the campaign.
EDIT: I posted this here because I'm doing this for the RotRL campaign... but, thinking about it now, it might do better in a different part of the forum :\
My brain hurts just trying to contemplate how much coding must have been involved to do this. Then again, I'm from the old school of roleplaying with lead miniatures, drawn maps, and dog-eared manuals. :)
That, and my Surface tablet already has issues trying to run the PDF maps that Paizo includes - I don't know why, normal PDFs run perfectly fine, but the map-only PDFs stutter.
There's no coding involved at all - at least not on my part. All I did is install programs and move things around.
Also, I don't use the PDFs on the iPad. I copy the maps out of the PDF, and paste them into PhotoShop for resizing and cleaning. PhotoShop is the only thing dragged over to the display. And since it isn't the iPad rendering it - it's my laptop - it's a relatively smooth experience.
And the 9.7" map really isn't an issue when you can move it freely.