2GB Memory RAM Upgrade for the Lenovo Thinkpad R61 Series T60 Series T61 Series X60 Series and X61 Series Laptops (DDR2-667 PC2-5300 SODIMM) - Walmart.com
Lenovo ThinkPad X61S T7500 Core (TM)2 Duo 2.00GHz 4GB RAM NO HDD - NO OS | eBay
4GB 2X2GB RAM Memory for Lenovo ThinkPad X Series X60 ( Type 1706 ) Black Diamond Memory Module DDR2 SO-DIMM 200pin PC2-4200 533MHz Upgrade System Specific Memory - Newegg.com
Lenovo ThinkPad X61 767593Y 12.1" Notebook - Intel - Core 2 Duo T7500 2.2GHz - Black - 2N54790 - Shoplet.com
2GB Memory RAM Upgrade for the Lenovo Thinkpad R61 Series, T60 Series, T61 Series, X60 Series and X61 Series Laptops (DDR2-667, PC2-5300, SODIMM) at Amazon.com
ThinkPad X61: The Subnotebook That Got a Second Chance - YouTube