How to get my contacts onto my iphone from my old phone?

I recently changed phones from the Htc Wildfire to the iPhone 4s, but I have no contacts on my iphone? And I still have the memory card from the Htc. How do I get the contacts onto my iPhone?

I did the same but in reverse I changed from a iPhone 4s to a HTC one V and I used Bluetooth to get my contacts over to my new phone

First save all your numbers to your sim card, then put sim card to your iphone, then take the numbers from sim card.done!