Lossless Ipod question

Thanks to all, I kinda thought I would have to re-rip them. Well its is only 5000 songs wish me luck and thanks again to all for you answers.

Yes, good luck.

But before you re-rip all those CD's, do just one or two of them and see if it's worth the effort to you. If you ripped them at a reasonably high bit-rate, 192 or 320, the difference you can hear in your system may not be worth all that time and energy.

If you're using the iPod as your source, the difference in quality between a high bit-rate mp3 and an Apple Lossless file may not be audible. If, on the other hand, you're using one of the computer hard-drive based possibilities to a DAC with USB input, a Squeezebox or an Airport Express connected to you main system it might be worth it to you.

Listen first, then decide.

"you can convert AAC into Apple Lossless... I just did it."

Just because you CAN doesn't mean you SHOULD. Sfar is spot on; the original compression of the CD track to mp3 discards a heap of data to end up with a file about 1/10 of the original, data you simply can't get back. Converting from mp3 to Lossless (or burning an audio CD from mp3's) simply expands the file with lots of interpolation. All iTunes is doing is changing the file type to AAC; it can't recover the lost data, but just tries to fill in the gaps with some high tech guesswork.
It will never sound the same as an original lossless rip.

Again I have to agree with sfar; judge whether your end use of the ipod warrants such high quality files before you re-rip all those tracks!