The first thing to realize is that you don't have to type a hash at the start of every line. (You used the word "star", but a star is this symbol: "*". A "hash" or a "pound sign" is this symbol: "#". Just so you know... :-) )

Any decent editor (and quite a few bad ones) will let you comment a block without really thinking about it. The trick is, finding an editor that you're used to. I don't really recommend learning vi (it's horrible to learn), but once you know it, things work almost without any concious effort.

For example, using vi, I do this, pretty much by reflex:

1. type "ma" (mark current line as "a")
2. hit "i" for insert mode, then type my comment
3. hit "ESC" (to exit insert mode)
4. type "mb" (to mark the new line (the end of the comment) as "b")
5. type ":'a,'bs/^/#/" (from line a to line b, match at the start of line, and substitute in a hash )
6. type ":'a,'b>" (optional: indent one level, add more > symbols to indent more)

You can do pretty much the same thing in Emacs, or any other editor you like.

Good luck! :-)