L.A.
What a cute idea! You could serve deviled eggs and ham. Serve alphabet shaped sugar cookies. And make crazy, colorful hats as favors. (more ideas heres)
http://entertaining.about.com/cs/kidsparties/a/drseusspar...
http://baby-shower.yeahbaby.com/theme.php?page=Dr-Seuss-b...
You could print large pics of Dr. Suess characters at Kinkos and use them on walls and such. Or laminate small pics and use them on the cake for decoration.
My sister makes really cute diaper cakes, that people use for center pieces and games too. She could make you a really great Dr. Suess themed one.
http://www.bumblebeebabyboutique.com
Or you can wear a cute Dr. Suess shirt, and get the baby a little gift set here:
http://www.seussland.com/apparel.html
And here's a downloadable Dr. Suess Baby Shower game (or make your own):
http://babyshowerjunction.com/babyshowergames/baby_shower...