does anyone no whats the best site to use for cheap calls abroad ... theres so many im want to call china

See http://callchecker.moneysavingexpert...ntcallchecker/

thanks found a site were they charge 1/2p a min

www.jajah.com can be handy.

Try www.extracall.com - 2p/min to China

Didn't you notice that, using the link already provided, the OP had already identified a provider charging ½p/minute (a quarter of that price).