I've been adding to my big page of Nokia E90 tips over on 3-Lib. If you've used it for a while as well and can add to the list, do please comment!

"As befits a communicator with a proper keyboard, Nokia have outfitted the E90 with lots of shortcuts, although it still falls a bit short of those in its full (Series 80-driven) 9500 predecessor. Here are a few of my favourites, some obvious (as they're similar to those in non-keyboard S60 devices) and some not so obvious:
In any text-entry application or dialog, Ctrl-C copies highlighted text, Ctrl-X cuts it and Ctrl-V pastes it, just as in any desktop application.
In Web, '8' brings up the mini-Map, '1' gives you bookmarks, '5' switches windows."

Read on...