Do you know a site where there are dancing classes to download? free, of course?
i'm trying to improve my skills 
) please answer seriously........only if you know
i am talking about modern dances.........:)
I guess the first thing I would ask about your question is what kind of dancing are you interested in?
I've been dancing for many years, but only recently have I done Ballroom Dancing. In my quest to learn Ballroom Dancing, I've found my local public library to have a collection of dance instructional videotapes and DVDs covering Jazz dancing; "wedding dancing"; American Smooth: Waltz, Foxtrot, Tango; Rhythm: Rumba, Cha Cha, Salsa, Merengue, and Swing (East Coast, West Coast, Lindy Hop, Charleston, Jitterbug) and separately: Argentine Tango, Country Line/Two Step/Country Swing, etc.
I also found CDs with appropriate ballroom dance music available in the library collection.
That said, you asked for "downloads" so here are some web resources I've used.
The learning center at ballroomdancers.com (link below)
The educational resources of college dance team web sites, like the Utah Rhythm and Dance site (link below).
I have also danced historical dances and have separate resources for:
English Country Dance (Including Jane Austen Dances)
Contra Dance
Square Dance
Round Dance
Medieval and Renaissance Dance (15th-17th Century English French and Italian Court Dance
International and Israeli Folk Dance.
I've answered for Ballroom Dance, were you interested in historical dance? I have found links for video footage for individual steps in Italian Court dance, for example.
Finnish Disco Lesson
