Are there any clipboard managers for Linux?
 

I've found some invaluable clipboard utilities for WinXP that allow you to save blocks of frequently used text and insert them into documents with a few keystrokes. They also keep a record of text you've sent to the clipboard and allow you to paste them into documents later- i.e. instead of only knowing the latest thing you've copied they remember several things at once and let you choose between them.

Is there any software like this for Ubuntu?

Well, KDE has klipper. Is that what you're looking for?
cheers,
jdk

Well, two clipboard managers such as you describe come to mind. One is installed by default on Gnome:

Gnome clipboard manager

The other is installed by default on KDE:

Klipper

The Gnome clipboard manager sounds promising but how do I use it/turn it on?

Right click on gnome-panel; add applet; drag clipboard manager to the panel

I don't see the Clipboard Manager listed as a choice to add to the panel. Nor is it a choice to install/uninstall in Synaptic. (I did find a "lightweight clipboard manager" called Parcellite and I installed that.) Is the other Clipboard manager still worth bothering with?

Sure I use parcellite as well. Just add it in startup programs for launching each time you login! Also you can right click on it and set the preference, how many clipboard history to manage.

xfce4 has Clipman.