A couple ideas to consider
Whats the best way to mount the surrounds on the corner of my room?
A couple of ideas come to mind:
For placement ideas a decent overview article is:
http://www.gcaudio.com/resources/howtos/speakerplacement.html
The article advises to keep most speakers out of corners by a foot or two minium to "minimize early relflections"--not always possible, but something to consider.
For safety, I would definitely find and use a wall stud whenever possible.
Also for safety, use speaker mounts rated to hold more weight than the speakers weigh. For instance I used 20 lb capable speaker mounts for my 12 lb surrounds.
Some speakers come ready for wall mounting, others you may have to drill a couple small holes inorder to attach the mount. Having done it, it was really no big deal.
Hope that helps. If you have more specifics it could get you better answers.
Cheers,