I am trying to download my contacts to my iphone4 from my old phone samsung galaxy...what do i need to do since the sims cards are different...i did not want to go to the sprint store

You need to try and transfer your contacts to something the iPhone supports. If you can upload them to something like Outlook or Address book on the computer, then you can upload them to the iPhone. The iPhone can also sync to Google contacts, which could be just as easy a solutions since you should have a Google account with the Galaxy.