[_ck_]

I think it will be something like this

<?php echo '<a href="'.get_profile_tab_link( bb_get_current_user_info( 'id' ), "edit" ).'">edit your profile</a>' ?>

(untested) the “edit” part is just a guess…

get_user_profile_link(bb_get_current_user_info( 'id' )) will get the profile link for general stuff, not the edit tab.