Intel Mac :: Increase Memory From 4GB To 8 Or More

I just bought my mac last month, and was thinking about down the line increasing the memory from 4GB to 8 or 16. But when I looked on Amazon, all I could find was memories and in the reviews everyone was talking about Macbooks, not iMacs. Could I use the same memory? 

Here's my system information, if it helps: Processor  2.7 GHz Intel Core i5 Memory  4 GB 1333 MHz DDR3 Graphics  AMD Radeon HD 6770M 512 MB Software  Mac OS X Lion 10.7.3 (11D50b) and:    Model Name:          iMac  Model Identifier:     iMac12,1  Processor Name:          Intel Core i5  Processor Speed:     2.7 GHz  Number of Processors:          1  Total Number of Cores:          4  L2 Cache (per Core):          256 KB  L3 Cache:          6 MB  Memory:          4 GB

Info:
iMac (21.5-inch Mid 2011)