Do you mean that "Matt's LimeWire Tunes" isn't showing in iTunes?

Within LW, make sure that you still have iTunes sharing enabled. Tools > Options > My Files > click on Configure, next to iTunes > tick both boxes > ok.

Close iTunes, restart LW & then open iTunes - see whether that helps.

If not, go back into LW's options & untick the boxes for iTunes sharing > ok. Restart LW & then go back into Options & tick the boxes again > ok.
Sometimes disabling/re-enabling the options is a fix

I'm using iTunes 7, but haven't heard of any other people having probs with iTunes 9 & LW.