5
I'm confused as to what you want to do. If you have XOOPS and mylinks then you don't need to use iframe. You're done. If you don't want other blocks showing up then don't set (unset what is there now) any blocks to show on the mylinks page.
It sounds more like you want to iframe an XOOPS module inside another site/non XOOPS site. That could be done too with the right XOOPS settings and theme.