I don't know much about hdd and sdd besides i have the option to remove the hdd (on my lenovo y50) and replace it with a much faster ssd (which also doesn't spin so it's less likely to be damaged inside the machine)
Anyways, once I take the 1tb hdd out what are my options with it? Or is it just a piece of junk until I put it into another laptop? Can it be used inside a ps3? Or as external memory?
You can buy an external caddy and reuse it as mass external storage or backup. You could put it in another laptop (or desktop)
It probably would work in a PS3 using a miniSATA to SATA cable, but it would mak an awesome external drive for backups and file transfers. As David said, just get an external drive caddy. You can get one for as little as $12 or so from newegg, although personally I like the higher quality ones.
David and Tumbleweed are correct. I would use it to Make an external hard drive.