LIMEWIRE
You can find them on Netflix and online.
Those can usually be found on youtube. I have the ones they released on dvd, so if you haven't found them, it will probably be easier.
you can go to wikipedia for the all the episodes and their descriptions. or you can go on you tube and watch videos for the episodes.
Legally nowhere. Illegally, well, you can google "Lost Episodes" and it surely will find someplace.
Target
A&E TV has the first 48 episodes online for viewing. You can also find episodes of friends available on Slide Share. There are several site beyond these that provide episodes of Friends.
Finding full episodes of Blues Clues in UK is easy. You can find the episodes online all you have to do is download them.
ABC.com streams all episodes that have already been aired.
You can watch the first episode in season 6 of lost on line at Hulu.com and abc.com. They have all the episodes aired so far. To see the episodes, just look through their television show inventory.
They're on iTunes now.