adding MP3's on desktop to ipod

Have an Ipod mini and iTunes (v 7)

I recently had occasion to have an audio book downloaded form a site that I usually purchase the CD's form as "gift" for past orders

I downloaded the MP3 file that was "for itunes"

it is an MP3 file

it will NOT play in itunes

I CANNOT add it to the itunes library by dragging OR by importing

If I burn the mp3 to a CD and then convert to an AAC file it will play import and play, but that seems like a lot of work

SO -- the questions:

1) why cannot itunes not import from the hard drive (desktop, or other folders)

2) how does one convert files from mp3 to AAC when they are on the desktop -- this seems to be only available when they are on a CD

thanks

mark


Windows XP Pro