Can you recommend any J-pop songs for me?

Try listening to Hey! Say! JUMP songs.

like:

Dreams Come True

Ultra Music Power

L'Arc-en-Ciel:

My Heart Draws a Dream

Seventh Heaven

Alone in La Vida

Yuki no Ashiato

Ready Steady Go!

Link

alice nine [this is jrock but they have really hot guys!!]

Waterfall

Jellyfish

Velvet

Arashi:

Love So Sweet [Hana Yori Dango OST]

Step and Go

Wish [Hana Yori dango OST]

Ikimono Gakari:

SAKURA

Blue Bird

Hana wa sakura kimi was utsukushii [Opening for Naruto]

For female singers try

Namie Amuro:

Should I Love Him

Can't Sleep, Cant eat, I'm Sick

Please Smile Again

Wonder Woman

Hide and seek

Do me More

Wowa

Body Feels Exit

Zeebra

Fake

You can also try Ayumi Hamasaki, they're both popular :)

Look at stuff by Gackt; he's kinda more J-rock, but his songs are pretty well known, and catchy.

(Vanilla, Stay Ride Alive, Ghost, etc)

SMAP / Lion Heart

http://www.youtube.com/watch?v=y55aGWG09Ck&NR=1

/ Sekai ni hitotsudake no hana

http://www.youtube.com/watch?v=xFufwcSue0A&feature...

Arashi / Happiness

http://pann.nate.com/video/211204626

Hey Say Jump / Mayonaka no shadow boy

http://www.youmaker.com/video/svb5-d1740491f3b14d2...

EXILE / Someday

http://www.youtube.com/watch?v=xkGZJbXEhAM&feature...

/ Choo Choo Train

http://www.youtube.com/watch?v=Rs1ynO9x0OA

Perfume / One Room Disco

http://www.youtube.com/watch?v=CRIlCv7r0jQ

Ai Otsuka / SMILY

http://www.youtube.com/watch?v=DpyP_1wCxTE

/ Sakurambo

http://www.youtube.com/watch?v=eGHDrlvypWg

Kobukuro / Tsubomi

http://www.youtube.com/watch?v=eaDY4M7KBPQ&feature...