From the Battlefield 3 Consoles Rent-A-Server announcement video:

"For the first time in Battlefield history, we are proud to offer console gamers the ability to rent multiplayer servers! Having your own server gives you the power to create your personal gaming experience.  You can rent and set your server up in no time right from the main menu. Tweak every setting, or choose a preset configuration and publish your server in just a few seconds. What maps and loads do you want to play. Do you want to show the minimap or not? Do you want to turn off HUD elements or tweak respond times and tickets? It's all there for you to decide. As this is your server, you can also make sure the people you are playing with are the people you want to play with.  Kick out any unwanted elements. You can promote friends to VIP status to reduce their waiting time if your server is busy. You can rent your server for 1 day, 7 days, 30 days or 90 days. Customize your server by giving it a name, description,  and custom logo. With your server live, go ahead and practice tactics with friends in the comfort of a private environment, or set up a public ranked match and start playing today on a server you know will have all the maps, modes and settings that you love."

You can select from several presets, including:

Normal preset: Normal mode uses the standard battlefield rules with all HUD elements visible, friendly fire off and regenerative health. Normal mode is both for the novice and pro plahyers that want to have plain simple fun!

Hardcore mode: Decreases the amount of HUD elements and soldier health, and disables regenerative health. It is not for the faint hearted and you need to take your team mates into consideration when firing because friendly fire is on!

Infantry Mode: Removes all vehicles from the levels except transport vehicles and gives you infantry vs. infantry gameplay where your aim is all that matters. 

If you choose a preset mode, you can still change additional server settings later. You can also choose a map rotation, including:

BF3 Classic Only: Classic Battlefield 3 maps and modes.

Back to Karkland Only: Back to Karkland maps in a mix of conquest and rush.

Epic Battles: Large scale conquest maps with a focus on vehicles and tactics

Prices may vary according to location. Prices as of the time of writing this article are:

USD
1 day: $1.49
7 days: $6.99
30 days: $24.99
90 days: $64.99

UK Pounds
1 day: £1.19 
7 days: £5.49 
30 days: £19.99
90 days: £47.99 

Polish Zloty
1 day: 5 zł 
7 days: 26 zł 
1 month: 89 zł
3 month: 218 zł