Amazon has the Corsair 4GB (2x2GB) PC-6400 DDR2-800 SO-DIMM 200-Pin Dual Channel Notebook Memory, model no. VSA4GSDSKIT667C4, for $26.15 (66.15 – 40 MIR) with Free Shipping. The $40 mail-in-rebate is good until June 15, 2009.

Corsair’s VSA4GSDSKIT667C4 is the highest performance PC and Mac memory solution for the MacBook, MacBook Pro, iMacs, and PCs alike. Increase your Mac or PC performance by as much as 20%, it allows users to maximize memory bandwidth and minimize performance bottlenecks to deliver a superior user experience. Built to Corsair’s legendary quality and reliability standards, each module is tested to ensure maximum compatibility. Each Memory module is individually tested and certified to be compatible with Apple products and PCs alike. It also comes with Lifetime Warranty.