2K Games confirmed that Gearbox's Borderlands on PC will get the same achievements as the X360 edition but only if you purchase the game through Steam.

Borderlands combines the best in first-person action with player customization and vehicular combat to deliver an exciting Role-Playing Shooter experience. The game features a groundbreaking content generation system allowing for near-endless variety in weapons and item drops. Borderlands allows for multiple players to share the same game experience simultaneously online in co-op gameplay. Players can freely join or leave each other's games at anytime, or choose to play in the full single-player mode. These features, along with a rich and deep fiction that touches upon the mysteries buried beneath the surface of a danger-filled planet, combine to form a breakthrough experience that challenges the conventions of modern shooters.

Get ready to face off with brutal, never-before-seen enemies in a huge new environment complete with tons of brand new missions.  Don't worry, you'll be able to get guns (yes, even more guns!) to give you the firepower you'll need as you discover entirely new weapons and items!

Borderlands Double Game Add-On Pack features the hilariously gruesome The Zombie Island of Dr. Nedand the finest next-gen display of Darwinism ever made, Mad Moxxi’s Underdome Riot.

The Borderlands Double Game Add-On Pack will be available for $19.99 on both the Xbox 360 and PC on April 6, 2010 in North America and April 9, 2010 internationally.

The Zombie Island of Dr. Ned

• The Jakobs Corporation’s little haven away from the badlands of Borderlands promises a relaxing experience for all visitors. All rumors of mutant skags, half eaten torsos and decaying zombies are probably false, most likely.  But, in the case they turn out to be true, we recommend purchasing firearms from conveniently located Jakobs Brand Vending Machines.  Please aim for the head.
• Dozens of new missions to explore and loot - hours of new single and multiplayer gameplay.
• New enemy types to blast away and dismember, but watch out, those disassembled parts can still tear you apart…muhahahaha!

Mad Moxxi’s Underdome Riot

• We heard some of you noisy braggarts saying that Borderlands was too easy. So, in an effort to challenge you so-called gaming experts, 2K Games and Gearbox proudly present Mad Moxxi’s Underdome Riot, a proper shooting and killing challenge. Ding, ding…it’s killing time.

Key Features:

• FPS Action Meets RPG Character Progression: Players can choose from one of four distinct characters and earn experience and gain proficiency in a number of specialties as they do battle with enemies. Upgrades can be invested in a wide variety of special abilities, allowing players to create a fully customized character that is tailored to their playing style
• Co-op Engineered Game Design: Borderlands is built from the ground-up to be an exciting and intuitive co-operative multiplayer experience that rewards players for investing in specific co-op skills
• Radical New Art Style: Fresh and exciting new visual style combines traditional rendering techniques with hand-drawn textures to paint a unique and eye-catching spin on the First Person Shooter genre
• Gun Lust: Choose from an arsenal of hundreds of thousands of weapons, each with their unique manufacturers, specifications and advantages. A revolutionary new content generation system produces almost infinite tools of destruction
• Intense Vehicular Combat: Get behind the wheel of and engage in intense vehicle-to-vehicle combat, complete with extensive damage modeling and spectacular explosions

Borderlands retails on PS3 and X360 for $59.99, and on PC for $49.99.