There is a bit more difference than expressed so far - depending on whose reading the poetry. Some believe true poems must have true rhymes - this is not the case with songs.
"oh, I've wandered so long,
baby, baby, wher've you gone."
This is called "assonance" - when the accented syllable on the last vowell sound matches, but the word doesn't ryhme.
Not a true rhyme but very popular and most definately acceptable in any song - other than the fact that this particular example sucks.
Most songs also contain a "chorus"
The main verse, usually containing the song's title - which is repeated at different intervals throughout the song.
Nan's partially right on the meter - that also would depend on the type of song. Almost all rap and a lot of country will have near perfect meter. All depends on the writer really.
If I can think of anything else I'll post it later but I can tell you this much - if your heart ain't in it - it will truly bomb. It's a lot easier to get away with a "flat, emotionless" poem than a song - that's because a song has to please more than just the eyes. You will have no problem songwriting with your talent though, overall, I find poetry a much more difficult challenge.