Don't panic! But Borderlands on the PC just had its release date delayed. Thankfully it's only been moved back six days from October 20th to October 26th. The reason? Adding that spit shine and polish the game so desperately deserves. According to Gearbox that optimization process is taking just a bit longer than expected.
The Xbox 360 and PlayStation 3 versions are unaffected.
Source: Au.pc.ign.com