Jpop recommendation  

sure! i recommend "Garagara Go" and "Bringing You Love" by BIGBANG. Don't worry, the songs are Japanese, not Korean. :)

Hmm...how about Matsushita Yuya. His songs "Trust Me" and "Honesty" fit that type of description. That was the only artist that popped in my head besides Utada Hikaru. Hope that helps.

hmmm...try to recommend these to your friend
nami tamaki ,,,koda kumi,, most of their songs has a dancy tune

My reply might be a little late, but anyway I'd recommend kat-tun, they have more dance-y tune songs, like Don't you ever stop (ohh, I love that so much, my favorite) or one of the newer songs D-motion, that has a real disco-ish feeling. It might be worth checking out arashi songs too.

I cannot be sure in recommending either but why don't you try DDR songs?

try listening to buono's songs. their songs are usually upbeat and for dancing. buono is an all girl trio dancing while singing.
amuro namie, mai kuraki, aiuchi rina, tenjo chiki are some that sings upbeat songs. but ofcourse, not everything that they sing is upbeat.

my favorite fast-beat j-pop song is great for an aerobic workout lol. it's called "drive me nuts" by cyber x feat. tomiko van

try songs by AAA(attack all around) they dance to most of their songs and its really nice

well
I recommend band of L'Arc~en~Ciel
Some songs of them will satisfy you.

this one song automatically strikes my mind as a jpop that has dance-y tune
THE D-MOTION by KAT-TUN