"Duolingo" i think is a great website for that!

Try Memrise, it's very useful!

I found Duolingo to be great for beginning learning, but it's a little diasppointing to start with such a wonderful resource and then struggle to find anything to follow it up with.

Not a website, but I found the book Swedish: Essentials of Grammar by Åke Viber, Kerstin Ballardini, and Sune Stjärnlöf to be very helpful with the finer points of grammar.

why do u want to learn swedish !!!!!! ? IT's first time to hear that someone want to learn this language !! Just curiousty :)

http://www.languagetutorial.org/learn-swedish/

Maybe this has something