How do I copy/move contacts from phone to my exchange account? My contacts are stored on a (Open-)Exchange server, so they are synchronized between phone, the server and my other mail clients (e.g. on my desktop PC).

However, I have some "phone-only" contacts and I want to copy or move them to my exchange server contacts.

How can I achieve this?
This isn't very elegant...  


Open the Android Contacts   app
Menu --> Display options --> Choose contacts to display  
Under each account, expand the list, make a note somewhere of what was checked, and then uncheck everything
Tap Done.  You should now be left with phone-only contacts
Menu --> Import/Export --> Share visible contacts
You will see some options for sharing a vcard file (.vcf).  You could email it to yourself, upload it to Google Docs (if you have the Google Docs app installed), etc.
Once you've confirmed you've shared the vcard file, unless you're feeling extra brave, do a quick backup of your contacts to your SD card: Menu --> Import/Export --> Export to SD card
Delete all the local contacts from your phone (long-press --> Delete contact)
Import the contacts you shared in step 6 (not the ones you backed up to your SD card in step 7, which will include all of your contacts) to Open-Xchange using the instructions on page 193 in the Open-Xchange User Guide.  More languages available here: http://oxpedia.org/index.php?title=Main_Page_CE#documentation
Back in the Contacts app, go to Menu --> Display options --> Choose contacts to display
Under each account, expand the list and recheck everything you unchecked earlier
Tap Done.  All your synced contacts should be visible again, including the ones you just exported (the next time your phone does a sync)