Wow! You're having a pawty! We hope you have tons o' fun!
Mommy usually does doggy themed birthdays for us. Scooby Doo (Roscoe's 1st) Blues Clues (Lily's 1st) Lily has also had Tinkerbell and Hello Kitty themed birthdays.
We have gotten birthday cakes from River Dog Bakery the last 2 years (Including the Knoxville Dogs Christmas Pawty). They are very yummy and reasonably priced.
Mommy usually does small treat bags for the doggy guests.
Food City also sells Dogster ice cream cups in the ice cream section. They have peanut butter and mint flavors. Great for a hot summer day. We love them.