I'm using Win XP, updated iTunes & QuickTime to most recent & using LW 5.2.13 & no problems with the user playlist showing in iTunes including music & video. Unlike LW 4, you do not see Library & user lists, instead you simply see the user shared playlist with drop down arrow.

* For the songs to appear in the shared user list in iTunes, it appears they need to be shared in LW. I think that means it operates differently to previous versions of LW which from memory showed all recently downloaded music. Under LW's Tools -> Options menu scroll down to iTunes options button & ensure share with iTunes is enabled.

Using another Win XP with updated iTunes & QuickTime & LW 5.3.4 Beta, the other account's LW playlist (one mentioned at of post) shows up fine as does the LW 5.3.4 playlist, and another from a mac computer.

Generally after installing/updating QuickTime you should reboot your computer.

I told him to do that earlier - sharing was enabled

I just updated to iTunes 9 as a test. My options are ticked to allow sharing with iTunes. My 'LimeWire Tunes' shows as per usual.

But - if I don't have files showing in Public Shared in My Library (ie being shared with the world), they don't show in my LimeWire Tunes in iTunes.
Add everything to Public Shared & it shows up in the LW playlist in iTunes. So looks like it's not just iTunes sharing within Options but adding to Public Shared as well.