I use a Mac and use Filezilla, I've got it set up so that once I've told it what I want to send and where I walk away and it just cracks on and does it. You can set it to upload more than one file at a time but I've found it's actually quicker to just do one at a time and when it's finished it moves onto the next file and then the next site.
I think that's what you're after.
Fetch, what I am using now, does what you are describing.
What I am looking for is a FTP client that will do batch uploads to 7 different microstock sites of one batch of photos (once I set up the right addresses and password). So for example I would like to drag 10 images to the program just once. Then walk away and have the softward automatically upload the 10 images to 7 different sites? Does Filezilla do that?