2000 protege sway bar clunk?
 

this is my second post. i just posted about an EGR valve. i have a 2000 protege with almost 100,000 mi. whenever i go over bumps, there's a clunking sound from, i think, the front driver's side. according to what i've read, this might be a sway bar? so i have a few questions...
- what's a sway bar?
- where's it located?
- if it's bad, what will i see?
- if it's bad, can i fix it and how to? i have minimal knowledge but love learning and don't mind investing some time and money.

interested in your thoughts. thanks for any replies!