Configure Dropbox as a service

First, run the Dropbox installer using the command line switch /D=C:\Program Files\Dropbox (with no quotes) to install Dropbox into the Program Files directory for all users.
Then here an updated version of the procedure given on this link:

Since Dropbox will normally only work when a user is logged in, we will have to install and use it first via remote desktop, before it can be turned it into a Service.

1. Remote desktop to your WHS as administrator
2. Get DropBox from their website.
3. Install and configure Dropbox as you like. e.g. I made a special share on my WHS named Dropbox before the installation and linked Dropbox to this share. Then exit dropbox from the system tray.
4. Similar to Foldershare, you will need instsrv.exe and srvany.exe from the Windows Server 2003 Resource Kit Tools.
5. Copy instsrv.exe to C:\Program Files\Dropbox
6. Copy srvany.exe to C:\Program Files\Dropbox
7. execute "C:\Program Files\Dropbox\instsrv.exe" Dropbox "C:\Program Files\Dropbox\srvany.exe"
8. execute reg ADD HKLM\SYSTEM\CurrentControlSet\Services\Dropbox\Parameters /v Application /d "C:\Program Files\Dropbox\Dropbox.exe"
9. execute reg ADD HKLM\SYSTEM\CurrentControlSet\Services\Dropbox\Parameters /v AppDirectory /d "C:\Program Files\Dropbox"
10. Delete or move the shorcut to Dropbox away from the startfolder (Start -> All Programs -> Startup) on the startmenu.
11. Move (cut/paste) ALL the files from C:\Documents and Settings\Administrator\Application Data\DropBox to C:\Documents and Settings\Default User\Application Data\Dropbox
12. execute net start Dropbox

After you're done: Start > Run > "services.msc"
Find your "Dropbox" service.
Right click on it and select "Properties" goto the "Log On" tab and make sure the "Allow service to interact with desktop" checkbox is checked.
Start/Restart the service as necessary.
You will either get a popup asking for permission to show the Dropbox configuration or the Dropbox configuration will just come up.
Put in your username/password, choose where you want to place your Dropbox (under the particular user you want) and you're good to go.
Verified to work on Windows Server 2008.