directory location of sync files? I am using my iPad with windows 7. So..everytime I connect my ipad to my pc, itunes downloads applications that I bought on iPad. So..to what directory does the Itune download purchased application from my iPad?

and..is there an option to prevent iTune from downloading apps from my iPad to sync?
For the first question, I think its actually stored under C:\Users\username\My Music\iTunes\iTunes Media\, if everything is standard. If anything, it will be wherever your music is also stored (just in another directory). 

As for your second question, I don't think you can tell it not to sync the apps. The only ways to not keep them would be to delete off your iPad before sync, or delete from the file system after sync.