They do a pretty good job with dog grooming at a very reasonable price. The price will vary depending on the breed (some dogs just need a wash, others need hair cuts, etc.). It's very easy to get an appointment and they recently started accepting credit cards. Nothing fancy here, but Fell's Point Pet Center is a pretty good place for the basics in a convenient location.
Please note: In addition to grooming, they also offer a decent variety of pet supplies. The prices on these seemed pretty average; no huge deals but you are supporting a local business when you purchase supplies from Fells Point Pet Center.