You can get an ID on Yahoo Japan and, if the 
seller ships internationally, you can bid on your 
own. The link I've put above will bring you to my 
Yahoo Japan Info page, which might answer some of 
your questions.

Just remember, for getting an ID and bidding on 
your own, you're a little out of luck if you 
can't (by some means) communicate in Japanese.

Many Sharp Smiles,
--Drac