What is the "hot key" or shortcut to toggle between open windows inside PhotoShop?

Thanks.

Command - Tilde (~), as with most Adobe apps,
and as Mike suggests, Control-Tab

(Once the Mac OS took over some of the controls
Adobe had to shift it's key functions.)

Control + Tab

Mike, you beat me by a minute.

Sorry.

But Chita beat me too. Both seem to work fine on my version of PS (CS3).

The attached PDF shows others.

Adobe_Help_Viewer_1.1.pdf (61 KB, 19 downloads)

OK ... thanks.

Command + ~ DOESN'T WORK. [ That's why I asked the question in the first place. I couldn't find the key command in online help or the Internet. ]

CONTROL + TAB works.

I'm using Photoshop CS1 (PS 8).

Command ~ does work.
That's why I mentioned the issue with Adobe changing the
keys. In some instances it may work 'slowly', or so to say that
the reaction times is sluggish, so it appears that it isn't working.
You may have to hold the keys longer in that instance, so
mileage may vary.

What it really is is a nuisance, that Adobe changed it here in PS,
but left the Command ~ function keys in the other Adobe apps.
Why change it at all?