Is there any nice guides to installing a new car stereo?

I am going to buy a new car stereo and am thinking of saving money and installing it myself, i have looked and have found no obvious way of getting my old one out. should i do it myself or get somebody else to do it? is there any good guides out there explaining what to do.
Answer
If you dont know how to do it, or are not familiar my advice is to let someone else do it. paying someone $75-100 to install it will save you a ton of headaches.