First, you would need an auxiliary cord to connect your mp3 to the boombox (I do this with my iAudio U2 and Bose Wave Radio 2). Secondly, it all depends on what kind of boombox you're using. If it has head phone and mic jacks. For iPod, I know some new Sharper Image products that will suit both of your needs. You should check out their website.
It is called ZipConnect, read the lower portion of the page for info relative to connecting to components.