Well I'm a true novice to this, but know how amazing forums can be as I've used for buying/exchanging stereo stuff so hoping someone can help me out.

I've just installed LimeWire basic, which is on a PC. Until yesterday, I had it working on my MAC, but decided to convert to PC.

I get the songs from LimeWire, I can see them on the ITunes, but when I sync the IPod it's not taking the Limewire downloads. Any clue what I'm missing???

Mac users can have files automatically added to the iTunes library...doesn't work that way for PC users The shared "LimeWire Tunes" that you see in iTunes is just a playlist & so you won't be able to add those to a playlist or move them to your iPod...those aren't actually in the iTunes library. If you turn off LW's iTunes sharing, or close LW, that list will vanish.

You'll have to add files to the iTunes library first, then sync your iPod. Have a look at this thread (posts #7, #8, #9 in particular) for heaps of info & tips
Transferring music to iPod & iTunes