i never did that before. i'm sure, that i need a progress bar to keep to user informed. are there some advises which way i should go? use a flash uploader (swfupload) or a "cooler" way with XMLHttpRequest.
thanks for an advise!
Try http://www.plupload.com/. It's already have upload progress status. But don't forget to send csrf in request. I'm using it on my shop at magnitofoto.ru: