Can I have my purchased iTunes Store items on two authorized computers?

Yes you can. There are many different ways. You can Burn them on a disc then rip the music on the other computer (this is also helpful if you want to back up your music just in case something goes wrong), you can also get a flash drive and transfer the music into the drive and to the other desktop, repeat that until all your music is transferred. Burning the discs may take a while so i recommend getting the drive at an Office Depot i got my 2GB drive there for under $30.

if you’ve got an ipod you can enable disk use (check box on the ipod’s summary page) and use it as an external hard drive to transfer those purchases over.

you can use an iPod in normal mode (at least on a Pc). Put your music on it from PC 1 attach to PC2 and then in iTunes don’t sync with the new library but instead choose transfer purchases from the menu.

I confirm that what LightlySeared says is true for Macs, too. And I’d bet it works on iTunes between platforms, too. iTunes will automatically popup a prompt to copy the authorized purchases into your computer’s iTunes Library… no special settings required.

If you have music from sources other than the iTunes store, Then you have to copy the files onto some other media to transfer it (e.g. CD, flash drive, or iPod enabled for disk use as Noah D suggests).

I have my entire iTunes library on two computers – my laptop (mac) and my desktop (win) – both work fine – you are allowed to authorize upto 5 computers.