I need your help! Please.

Hi ladies.
Well my son is turning 3 in a couple weeks and i want to get started on his birthday invitaions! I was trying to see if any of you mommas know where i can custom the invitation or if you could give me a sample what i could do.
I'm thinking of doing his theme either Thomas the Train or Toy Story.
What would you do with either one? Please help me. I've been looking for 2 days.

I know on shutterfly.com you can create invitations and things like that