[wp-testers] PHP/WP profiler tool?

[Doug Stewart]

Howdy all:
Anyone know of a quick-n-dirty way for me to figure out what exactly
is slowing my site down?  I'm hosting four blogs on one server and
have kitted the others out with minimal 1.6 installs.  Mine is running
1.5.2 with a boatload of plugins.  I'd like to keep as many of them as
possible, but I'd like to figure out which, if any, of those plugins
are responsible for the s l o w  a s  m o l a s s e s performance of
my main site.

Suggestions?

-Doug Stewart