I'm a guitar noob as well and I've been playing around with Rocksmith on PC. I don't think it replaces a real teacher at all but if you want something fun as an alternative and a way to learn popular pop/rock songs I suggest you check it out.

You can use it to practice like this post's article. You can repeat sections and slow the tempo down. I'm not a fan of how the game ramps up song difficulty (IMO I think it starts way too easy such that the practice is not useful), but you can tweak this really easily.