Hello..Jor..Please see responses below:

1. Where do I find a step-by-step guide to using the SDK and building an app? I found another post about this but the link to the article was invalid.

Here you go:

http://www.touchsmartdevzone.com/article/95/An-HP-TouchSmart-Application-Deve...

2.  We just need this to run off the machine. Does the app need to be hosted/registered? How does that work?

If you need to run your program as a part of TouchSmart application (i.e. you want to fuse your program among other TouchSmart hosted apps (like Notes, Music etc) ) you need to register it as described in the tutorial above.

 If you want to create a stanalone touch application, you need to refer to MSDN and you can create standalone touch application, basically a standard Win7 application.

Hope this will ease your process of development. Let me know if I can help you further.