I'm not sure what's going on from your description, so I'll try to describe the steps and throw in some pictures.
First of all, try to knit flat before trying to knit in the round. It will make more sense to start.
For knitting flat:
Cast on stitches. This is one of the most effective, simple cast ons around; I use it pretty much exclusively for everything.
It's the first one, called Long Tail or Continental Cast On.
In the first picture, you'll see ten cast on stitches with both the tail end of the yarn and the yarn going to the ball, which we'll call the feed yarn, coming from the same place on the needles. This is as it should be. The picture is a little decieving becase it looks like they are coming out of different ends; they're not, it's just a bad picture You will ignore the tail yarn while you knit... when you are done with your piece, there are ways to weave it in so it disapears into your work, but you will pay it no more mind now.
In the second picture, I'm holding the needle with the stitches in my left hand. The yarn over my fingers is the feed yarn, the yarn going to the ball. It is very important that you do not inadvertantly pick up the tail yarn and knit with it; you'll just have to pull out a lot of stitches and start over. I absent mindedly do that periodically and it can get very irritating The empty needle, that we'll call the working needle (as you will work the stitches over on to it) is on the right and you will hold that with your right hand.
Begin to knit. You will be knitting stitches from off the left needle onto the right, working needle. See the video's on Amy's site if you get hung up. The third picture is mid way through the row. The tail yarn is left alone, and the feed yarn is attatched to the stitches on the right working needle now.
The forth picture is looking at your completed row. The feed yarn is now coming off the end of the needle, towards the point. The tail yarn is on the other side, still ignored.
The fifth picture (in the post below; I ran out of room in this one) is of the work turned, or flipped over so what was the right working needle that you just worked all your stitches onto is now in your left hand. The feed yarn is coming off the tip. The empty needle is now the right, and has now become your working needle.
Rinse, lather, repeat.
If this doesn't solve the problem, let us know. I'm sure someone can try to explain. However, going to a yarn store near you will probably help a great deal; there will almost certianly be someone there who can help you sort it out.