If you don't have a lift, then as you know, you must have safety jack stands to support the car after you jack it up. Also, wheel chocks. Otherwise you can't safely go under the car to loosen the caliper bolts.
http://www.extremehowto.com/xh/article.asp?article_id=60246
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http://www.troublecodes.net/articles/frntbrks.shtml
http://www.extremehowto.com/xh/article.asp?article_id=60199