the topic of machine quilting is the topic of several ongoing "conversations" here. do a "seaqrch" on "machine quilting", "freemotion quilting", "free motion quilting", etc. and you'll find a wealth of information.
the most recent thread started on the subject is "how do you stipple?". it's not too far down the "Main" list from this thread. no farther back than page 2. check it out.