MEME suite with several different tools: http://meme.nbcr.net/meme/
Try different programs:
MEME-chip probably most appropriate for this dataset, but try others to see what you get
TOMTOM compares motifs to databases of known motifs to find matches. Some of these programs (MEME-chip) does this automatically for you but for others you have to paste the discovered motif into the program.