[losvedir]

Strange that Cmd-backtick doesn't work for you. Try this: Open up System Preferences, select "Keyboard", change to the "Keyboard Shortcuts" tab, and highlight "Keyboard & Text Input" on the left. Is the "Move focus to next window in application" box checked? What's its shortcut?

Also, long-clicking on the dock icon just activates Expose for Application Windows. I have it set-up to activate upon mousing to the top right corner and really like it. You don't have to wait for the delay of clicking and holding on the dock, though you'll still have to scan for the correct window.