There are currently two methods to remove the MegaVideo limit on the amount of time you can watch videos.
These methods are:
Illimitux
MegaStreaming

Illimitux
For this, you will need the Firefox web browser.
Illimitux allows you to remove the limit on more than just Megavideo. This is a Firefox addon.
Don't have Firefox? Get it!
Get Illimitux
When it is installed and you visit a page with a Megavideo video, a little popup in the corner of the browser will come up.
Click "Remove limit" and you will be redirected to a page with the video without the limit. Enjoy!

There are advantages to using Illimitux over MegaStreaming. MegaStreaming only increases the limit instead of getting rid of it. Illimitux is completely automatic, and it completely removes the limit.

MegaStreaming
MegaStreaming is a website that increases the limit on Megavideo videos. It isn't as good as Illimitux,
but it is a good alternative if you don't have Firefox and you can't get it.
MegaStreaming Site

Extras List:
Extras Main
Music Player
Remove the Megavideo Limit