How do I purchase & Install a larger hard drive for my Imac?
Mac OS X (10.7.3)
IMHO opinion the wise thing to do would be to take the machine to an AASP in your area and have them do it for you. Based on your question I'm guessing you may not have the expertise to do it yourself, working on an iMac is NOT for the faint of heart.
Do an online research for the type of HD that will suit your model iMac.
For install install instructions for your model iMac, go to iFixit.com and search for instructions on YouTube's How To tutorials.
If it's a Late 2009 or newer, check out > Upgrade Options on New iMacs
Optionally, there are lots of ways to free up space.
How To Quickly Free Up Hard Drive Space on Mac OS - YouTube
10 Tips to Free Up Hard Drive Space in Mac OS X - ChrisWrites.com
5 Quick Tips to Free Up Disk Space in Mac OS X
To include moving your iTunes, iPhoto and iMovie Library's to an external Hard Drive.
iTunes for Mac: Moving your iTunes Media folder
iPhoto '11: Move your iPhoto library to a new location
start up disc dosn't have enough space
