Live chat is really simple to get on to... just click the "Help" link on the top left of the page... then hit the big blue "Contact us" button... on the next page, select "Buying"... then select "Paying for items"... finally, click the "Chat with us" link on the left of the page.

You have to let them know what your issue is in relation to, hence the steps as listed above. Personal experience indicates that they join the chat within a few minutes - usually less than one minute, though - and you even get a transcript of the communication emailed to you after the chat session is closed.

Alternatively, you can select the "Have us call you" link below the "Chat with us" link. I've used this option three times, and find that they usually call within 3-7 minutes

For the average Joe, contacting eBay CS is a million times easier now than it has ever been