Jeff Waugh

Automagically link Twitterish “@name:” replies in comments.
Note: It hasn’t been tested on versions earlier than 2.1, but may very well work.

@reply

Automagically link Twitterish "@name:" replies in comments.

bingu

[ATTENTION] WordPress version MUST up to 2.7
Enhance the threaded comments system of WordPress 2.7. 
When someone reply to your comment, send a email to you.

replyMail

Enhance the threaded comments system of WordPress 2.7. When someone reply to your comment, send a email to you.

@reply vs replyMail