There is a lot of websites that let you watch tv episodes and/or movies online. You could probably find the episode you're looking for on either one of these sites:
www.bedroommedia.com www.surfthechannel.com www.Hulu.com (if you're in the states) And honnestly, Google is your friend. If you can't seem to find the episode you're looking for, you could always download it via torrent from: www.isohunt.com www.mininova.com Or any other torrent site.
season five, episode 18 its the last episode of the season.
Season 9 - Episode 23 - King Of The Hill
Thats an oddly specific request
Season 3 Episode 15: Just Watch the Fireworks
season 6 episode 24
season five, episode 18 its the last episode of the season.
Season 9 episode 13!
Season 9 - Episode 23 - King Of The Hill
Thats an oddly specific request
Season 3 Episode 15: Just Watch the Fireworks
season 6 episode 24
Season 4 Episode 9
Yes they do and eventually they get married
season 2 episode 10 x
Season 1, episode 19 of one tree hill. :)
Season 8 Episode 13: The other half of me
The last episode in Season 6 Remember Me as a Time of Day Episode 24 - Season 6