I just updated my Mac OS X 10.5 (Leopard) to 10.5.2. What I noticed was that two new icons appeared in the menubar, namely one for (.Mac) Syncing and one for Time Machine.
The removal of the Time Machine icon was straight-forward, the option being plainly obvious under the Time Machine tab in System Preferences.
What wasn’t so obvious, however, was the removal of the .Mac Syncing icon. As I do not use Apple’s .Mac service, I would rather not be reminded of it.
The removal of the icon can be found in the iSync application (which can be found via the Finder under Applications > iSync).
Uncheck the checkbox that says “Show status in menu bar”, and the icon will be removed.
Update: For a quicker way of removing the icon(s), you can hold the Command key and drag the items off the menubar.