There are some things I have given up ever coming across in my lifetime, and one of them is a pair of jeans that's the correct length. I'm short (5' 0"!), and even jeans in a "short" length are still a couple inches too long (never mind anything in a "regular" length). Fortunately, I learned a little trick in high school for hemming my jeans while keeping the original hem. While I'm sure I'd get a much better result taking my jeans to the tailors, this method is fast and free.
How to Hem Your Jeans and Keep the Original Hem:
1. Try your jeans on and cuff them to the length you wish they were. It's a good idea to try them on with the shoes you think you'll be wearing with them, since you'll probably want them a little bit longer for heels. I usually stick a straight pin at the bottom of the cuff so that it stays in place when I take the jeans off.
5. Turn the cuff up into the inside of the jeans. Ta-da! The hem job is not noticeable at all when the jeans are being worn. If you find that the bulkiness of the cuff inside the leg is bothering you, you can trim it down (leave about half an inch above the seam to accomodate fraying). I'd definitely wear them a few times and make sure you are happy with the length before you do this, though.
I will say you'll get better results the less you have to take up the jeans and if you're working with non-stretch denim. But overall, this is a pretty fool-proof method and only takes about 30 minutes.