You could get the apple adapter listed here
http://www.ebuyer.com/product/161949 it works well for me and has some advantages over the Accell like higher refresh rate support.
The downside is that you need a female mini displayport to displayport adapter which I couldn't find in the UK but I got one from here
http://estore.circuitassembly.com/products/Mini-Displayport-Female-to-Displayport-Male-Adapter-Cable.html and recieved it in 3 days. It also works fine for me even though they seem to have added a disclaimer recently about compatibility.