Partition manager that can handle LVM?

In RedHat's set of administration tools, there's system-config-lvm, which is optionally installable in other distributions like Fedora and Debian.

Recent versions of gnome-disk-utility support LVM.

The newly-released KDE 4.6 gains udisks as a Solid backend, which should provide LVM support. (Out of the three, this is the only one I haven't tried.)

In KDE there is 'kvpm' available.

I use it to handle all LVM related issue when I have a GUI available.

sudo apt-get install kvpm

What you really want to use is the lvm2 command-line tool lvm to ensure complete control over how things are setup and managed.

I know, how snarky and elitist of me. The minimal set of commands you should learn are {pv,vg,lv}create and their ^create^re{move,size} counterparts. Particularly with the -r|--resize flag for resizing.

This is very simple to figure out, and you will thank yourself graciously for not falling on the GUI utilities that are highly limited in functionality. I promise.