i have a couple of Questions about Electrum servers:
1. who creates and maintains these servers?
Volunteers. You can find out about them on the console tab of the electrum window.
2. why? i mean where do they get the money to do this, since Electrum is free.
Mostly they pay for it themselves. They take donations too but it doesn't amount to much:
https://bitcointalk.org/index.php?topic=573951.03. what kind of information do i send to these servers when i connect to them?
You send all the addresses in your wallet. They then reply with the transactions involving those addresses.
4. is there any difference between the servers?
Yeah, there are limits of how many addresses you can lookup or something. That is why you have those numbers next to the server names in the server selection window.
5. is it the same as other light wallet clients like Multibit?
No, multibit doesn't rely on centralized servers. It uses bloom filters which are a clever way of asking for transactions from lots of full bitcoin nodes and building up a picture from that.