URL Fixer corrects typos in URLs that you enter in the address bar. For example, if you type google.con, it will correct it to google.com (asking first, if you enable confirmation).
Its work on dlt .com, .net, .org, .edu, .gov, .mil, and all other mainstream TLDs, as well as the protocol (http:, https:). By right-clicking on the address bar, you can set it to auto-correct your errors, or you can have it ask you before making any corrections.
I am aware that there are similar extensions out there, mainly URLSpell and Firefix.
Add to Firefox