I am finding that using stitch markers every 20 chains has been very useful in keeping track of this bottom-up bag pattern. I use a different color marker for the beginning pattern stitch.

Gratuitous puppy and keeter photo for your enjoyment. :-)

Update: 6/3/2011 - I have gotten so many compliments on this bad that I have decided to make another one.

Update 7/1/2011: Made another one and gave it to a friend as a bridal shower gift.