I can understand that this is gonna seem like a stupid question , but I've recently bought a 2GB SD card. Now the digital camera I currently own is a Sony which only uses the Memory Stick cards which I transfer straight to my PC. Is there any adapter or anything I can use to transfer the pics from my hard drive onto the SD card so I can use them on my Wii or will I have to get a new camera ? Any help would be appreciated thanks.

Get a USB mulitple card reader and plug it into your PC. You can copy from your memory stick to an SD card. Here's a link of an example:

http://www.lexar.com/readers/multi.html

My laptop has one built into it so I use that to copy pictures from my Sony Memory Stick to the SD card.