So far, 2 seasons have been finished, at the end of the 3rd season, they will have a big movie called "Phineas and Ferb: Across the Second Dimension" this summer. However, I do not know when it will end, there may be more to come. Hope this has helped you.
They have made Season 1 -26 2 -39 3 -35 or more Total 100 or more
2 dimensions
Because they are only ten silly!
The series never says, but there are many fan theories. Most of them think that Dr. Doofenshmirtz is their real father. Here are some theories related with with their real father: http://disappearedflynn.wordpress.com/ in one of Dr. Doofenshmirtz flash backs the one where the phineas and ferb reverse engineer Dr. Doofenshmirtz inventions he was dating Linda (Phineas's blood mom) so that might mean that he had Phineas with her.
Phineas does not have a girlfriend but his friend Isabella who lives across the street has a huge crush on him and it is hinted that he likes her too, Isabella even kisses Phineas in the Phineas and Ferb movie but they both have their minds whiped so they forget it ever happened.
57 episodes in total.
As of now (June 22, 2011) there are 100 episodes.
Forty seven
It is a very enjoyable show. Many of the episodes are great and most are funny. I love watching them because they are cool.
They have made Season 1 -26 2 -39 3 -35 or more Total 100 or more
There is?
There are 100
2 dimensions
four worlds
3 trillion
Yes there is. It is on Phineas And Ferb on Disney Channel.
Because they are only ten silly!