Yes, you can! If a blog you read is using labels and also has site feeds enabled, then you can pick and choose which topics you want to subscribe to. The format for label feeds is this:
Be sure to substitute in the correct blog address for
blogname and the label you're interested in for
labelname. Also, don't miss the hyphen ("-") in the URL. That's not a typo!
Note that a URL of this form will only work if the blog in question is using this specific label, and has also enabled site feeds. However, no special site feed settings are necessary. As long as the basic site feed for posts is enabled (with either short or full descriptions) then label feeds will also work.