It's real simple to do! (I'm assuming you've downloaded the stand-alone server, right?) This looks like a lot, but it really isn't.
Open the BF2ServerLauncher and click 'Add a new config file' (It's the little blue + icon at the bottom) Lets call the file 'LAN' for simplicity.
Then configure the server exactly how you want it, including the maps you want in the rotation. Once this is done, click the save button and close the app.
Now open up your 'My Documents' folder, and look for the folder '\My Documents\Battlefield 2\ServerConfigs\'. You should see a file called 'LAN.con' in there. Before we open this file, create a new text file called 'mapList.con' in this same folder. Once created, open it in notepad. Now Alt-tab back into the folder so we can open 'LAN.con' in notepad. When you open this file, scroll to the very bottom and you should see your map list there. Highlight the whole map list, and cut it to you clipboard(we do not want the map list in this file). Now Alt-tab back into the 'mapList.con' and paste the cut map list into this file. It should look something like this:
MapList.append wake_island_2007 gpm_cq
MapList.append strike_at_karkand gpm_cq
MapList.append mashtuur_city gpm_cq
MapList.append gulf_of_oman gpm_cq
Now you can add the map sizes to the end of each map, which would now look like this:
MapList.append wake_island_2007 gpm_cq 16
MapList.append strike_at_karkand gpm_cq 16
MapList.append mashtuur_city gpm_cq 16
MapList.append gulf_of_oman gpm_cq 16
That's it as far as the config and map list is concerned. Now we need to create a short-cut to start the server with these .con files.
Open up the folder 'C:\Program Files\EA GAMES\Battlefield 2 Server\' and find the file 'bf2_w32ded.exe'. Right-click it, and 'Create Shortcut', rename it to any name you wish(LAN would be good). Now Right-click it again, and choose 'Properties'.
In the target field, add the following to the end of the string:
+config "@HOME@/ServerConfigs/LAN.con" +mapList "@HOME@/ServerConfigs/maplist.con" +modPath mods/bf2
The whole target string will look like this: "C:\Program Files\EA GAMES\Battlefield 2 Server\bf2_w32ded.exe" +config "@HOME@/ServerConfigs/LAN.con" +mapList "@HOME@/ServerConfigs/maplist.con" +modPath mods/bf2
Note: If you're going to run Special forces, you'll want to change the +modPath setting to "+modPath mods/xpack"
That should do it! Pretty simple eh?