add it by going to Edit Profile and scroll down that page until you see the SoundClick field,

an image will appear under your avatar with a link to your SoundClick page,

if there are any other music sites which allow you to upload your music an dyou would like them to be added to the edit profile page then reply here with the site and if enough people use it i'll add it

/* i know a few people have had a bad experiance with soundclick, this thread is not for hating on them */