Here are my top 10 tips to make using the Harrier a little more friendly than it already is (you may already know most of them but I hope there is something new in here):
1. When connected to the internet, the battery life is reduced. A quick way to disconnect from the net is to hold down the Red phone-hang-up button for about 5 seconds.
2. You can dial any number in your contacts while holding the Harrier in one hand without using the stylus.
i) Press the contacts button at top left
ii) Use the navigation pad (bottom centre) to scroll down the list of contacts. If you hold the button down (or up) for a second or two the display will scroll by letters of the alphabet so you can quickly move through a large number of contacts.
iii) Use the navigation pad's centre button to select a contact
iv) When the contact is displayed, scroll to the number to dial (if >1) and then use the centre button to select it and dial.
3. You can do the same one hand trick with emails in the messaging application by moving around with the navigation pad and selecting with the middle button. You can also display the context menu by holding down the centre button (good for deleting emails). You do have to touch the screen to connect and retrieve new emails if you don't have it on automatic retrieval.
4. Pocket PC does not actually close many applications when you close the window. So install an application to really close them. I like vBar (http://www.vieka.com/vbar.htm) because it is small, fast, and reliable. It won't actually close the phone application, but you can use the Red phone-hang-up button to close the Phone window.
5. If you go into a meeting and put the phone on vibrate, when you come out you can quickly put the volume back to your previous settings by pushing the volume slider up once.
6. Speed dials work in the same way as most normal phones. So if you have created some speed dials, you can just hold down a number key to dial that number. The numbers are big enough you don't need the stylus (so long as you don't mind finger prints on the screen).
7. You don't need any special software to change the Today screen picture. Just take a photo then view it using the "Pictures" application (not Album). Then use Tools->Set as Today Wallpaper to display it on the Today screen.
8. You probably know that you can use ActiveSync to update your calendar and contacts on the Harrier, but did you know you can copy all of your Harrier "My Documents" files to your PC using the Files option of ActiveSync. It is a quick way to copy photos to the PC. Just be careful though. If you delete a file from the PC it will delete it from the Harrier next time you Sync.
9. You can set your screen to landscape mode using Settings->System->Screen->Landscape. But a quicker way is to assign a button to do the job. Go to Settings->Personal->Buttons, then select a button you don't use for anything (I chose the button 8 "record"). Now select
10. Adobe have a PDF viewer for Pocket PC. It is large (over 3MB) but it does work well and has a special Reflow mode that allows you to reformat the PDF to display on the smaller screen better. Great for reading technical documents on the plane.