If you have little knowledge of astrology other than your Sun sign, here's how to get started.
You can sign up for a free account on Astrodienst which is full of information and articles from absolute beginner level to more advanced studies.
Go to the Extended Charts Selection, enter your birth details and and you'll get your chart drawn up instantly. If you don't know the actual time of birth, enter time unknown, and you will get the planets and aspects, but not the rising sign or house cusps. The moon degree will be not be exact either, as the moon travels fast, spending roughly two days a month in each sign , but if it falls around the middle degrees of a sign you can be fairly sure that the sign at least is correct.
Another good site for information on deciphering the basic meanings of planets, signs and aspects is Cafe Astrology.
Many of these sites offer computerised chart readings. These are basically a list of stock interpretations of aspects within your chart, and while they can be a useful and inexpensive way of getting started, they bear no comparison to the kind of synthesis offered by a personal reading from a real human being. Just so you know:)