On hulu.com
Youtube is bound to have it.
Try the Fox website. They have many of Glee's episodes in full for free.
Glee season 2 episode 16- Original Song
season 2
Season 2 Episode 2 :)
Episode 8- Furt
Season 1.
Season 2 episode 1 I think
Season Two's regionals episode was Season 2, Episode 16, "Original Song".
The episode was called Britney/Brittany. It is Episode 2 of season 2
Season 2, episode 7- The Substitute