iMac Intel 21.5" and 27" (Late 2009-Mid 2010) SSD Upgrade Bundle - iFixit Store
Amazon.com: OWC 2.0TB HDD Upgrade Kit Compatible With 2009-2010 iMacs, Includes: Thermal Sensor, Tools, 2.0TB Hard Drive : Electronics
iMac Repair & Upgrade, Same Day Services
iMac 27 Inch Mid 2010 SSD Upgrade
OWC SSD Upgrade Kits For 21.5-Inch iMac 2010
Replacing HDD with SSD in iMac 2010 | Yktoo
My 12 y/o son is so excited. Found him a pristine Mid-2010 27" iMac for $100. Going to give it the SSD upgrade but he's stoked to start recording music with it :
Installing additional SSD in Mid-2010 27" iMac
How-To: Now's the right time to swap your old iMac's hard drive for a fast new SSD - 9to5Mac
HD Upgrade Kit for all iMac 2011 Models + Tools - 44.75EUR - OWCshop