Nope--it's not true. You can redistribute eBGP routes into any other protocol (though I would question why you'd want to). iBGP can be done too, but it's not as easy, it's not (generally) safe, and it's _not_ recommended in any way shape or form.
Redistributing eBGP into an IGP with heavy filtering isn't unheard of, but a single mistake letting all the internet routing table into the igp, 150,000+ routes, would be a real network killer.
Russ