I started knitting a few months ago, and so far all of the patterns I've done came from the Free Patterns tab at the top of this site. It's so fun!
As for gauge, it's basically making sure that your knit style, yarn thickness, and needle size make the size stitches appropriate for certain sizes. In other words, 2 people who knit with the same pattern, yarn and needles may come up with completely different size sweaters if one knits really tight and the other knits really loose. Make sense? I've been told that gauge is basically for clothing items, and other things where the final size is important. Otherwise, if you're knitting a scarf for yourself...who cares if the gauge is completely wrong if you're happy with it? Oh, and it's done by knitting a few stitches/rows and then measuring the number of stitches/rows per inch.
[size=2]Okay, that sounded like I have way more experience at this than I really do. Hope I didn't give anyone that I'm-the-greatest-knitter-in-the-world-even-though-I-hardly-have-any-experience vibe![/size]