oOHh, that`ll be fun, that`s a long time! uhmm.. i know right off the bat that hamasaki ayumi will have her "countdown live". there are normally two performances and not just one, cause just one.. would be kind of a waste of a nice set and everything, ya know? tickets normally go on sale a little later and start at... i think 6,500 yen? i dun remember. but the two performances are on dec.30th and dec 31st. both are held at yoyogi hall which is literally a 5 minute walk from the harajyuku train station (going right), and then from yoyogi hall is literally another 5-10 minute walk to NHK hall (if just curious, heh, all next to each other). hope this helps if didn`t know already~. i can tell you i went to ayu`s countdown last year, dec 30th performance, and it was awsomely rockin`! such close view too! good luck w/ the concert find. if i find anything randomly, i`ll post another reply!
-bu