Can I plug my iPod directly into an amp?

Yes, you can. But the sound will be crap as you have to use the phone out rather than the dock's line out (which is pretty good sounding).

True but if you have the files in Apple Lossless compression or uncompressed WAV files or use Exact Copy, its OK (not great but not crap). Cardas has a cable exactly for this (using the headphone connection in the iPOD) as does I think Audioquest. I use the Cardas and the sound quality when done this way is OK, sorta like a cheap CD player. I know its not saying much, but you gain the flexibility of the IPOD and playlists etc....I use it for background music at parties etc...obviously not for serious listening.

My mistake! I misread your question.....I was describing a connection to a pre-amp not power amp directly. My apologies.

Can any one tell me what is the difference between the phone-out and the dock line -out? i went to the local store and they told me that the dock line-out does not add any gain to the signal..thanks

I have my 10GB 3rd Gen iPod connected using cheap 1/8" to RCA connectors to an Adcom GFA545II, which power Meadowlark Vireo bookshelf speakers.
Incorrectly set up (due to space constraints) in a small office, I've been stunned with the involving sound quality that results. One has to be careful to ensure the amp is OFF when connecting and disconnecting the iPod, otherwise, this can be done. And no, they're not lossless files, just 2,500 AAC files on an old player. Of course it can get better, perhaps using the dock connector and preamp. But I'm pretty picky and my Otolaryngologist tells me I have "perfect" hearing, so you owe it to yourself to give it a try. The pleasure this setup yields is constantly refreshing and gets me through long days at the office.
Cheers!