Foo - iPod/iTunes question

Alright, so I'm wondering if I have some files on my iPod which are not currently in my iTunes library, will those files be deleted when I synch back up to my iTunes?

I am not talking about synching to a new computer or anything, but back to the computer I am currently synched to.

I currently use Floola, a program which allows you to upload/download files onto your iPod from any computer. This has been great for me while living in China, as I've been able to download a ton of new music and put in on my ipod. So I'm worried that when I go back home and synch back to my itunes, will all that new music I added since then just be added to my itunes library, or will it get deleted?

I guess I plan on copying most of all my new files onto my computer back home before synching it to itunes anyway, but I am just wondering about this. Anyone have any experiences with this?

so here's the thing, when you hook up your ipod to your computer, and the itunes alert pops up saying something along the lines of "your current ipod is not synced to this library, it is synced to another one. would you like to sync to this library?" hit NO. and the ipod will show up on the left side. from there, go to the options and click "manually manage music" instead of "automatically sync." that way, you can drag/drop any music to add it to what's already in there.

does that make sense?

what you can also do is take all your music out of the ipod first, put it all in one folder on your desktop or something, then you can disconnect, add those files to your itunes library, connect again and when it alerts you to "do you want to sync to this new library?" click yes, and it'll delete your ipod stuff, but add what's in your itunes library, which should be what's in there plus what you added.

does that make sense? (sorry for asking this a second time)
also, and this is important for getting the songs out of your ipod, do you have a mac or pc?
edit: also, person below me makes a good point, what ipod do you have?

I'd use an iPod backup utility just to be safe. Some models of iPods like the Shuffle can be synced with iTunes on only one machine, and syncing with another means that your iPod gets erased.