If you only hopped on the Call of Duty train recently, or maybe played Modern Warfare on console and always wanted to see what it was like on PC, Direct2Drive has a deal for you. Pre-order Call of Duty: Modern Warfare 3, and you get Call of Duty 4: Modern Warfare for free. The only requirement is that you pay for your pre-order in full. As soon as you do, Modern Warfare will be ready to download. And for those who already pre-ordered from Direct2Drive, yes, the offer is retroactive.

More from Call of Duty XP coming soon »

Stronghold 3 and Tropico 4 are just around the corner. To entice gamers into pre-ordering the upcoming titles, both Steam and Direct2Drive are offering a number of bonuses.

Both titles feature a free copy of older games in the series, while Steam's Tropico 4 offer also includes some additional bonus content.

READ MORE: Freebies included with each order »