Here’s a regexp that validates email addresses – this is the most robust pattern I’ve seen, should work against any valid email.

Not sure why, but it fails in AS – at some point I’ll go through the whole thing and modify it to work with ActionScript, but for now I use a much simpler version:

[as3]/^[a-z][\w.-]+@\w[\w.-]+\.[\w.-]*[a-z][a-z]$/i[/as3]

and another I use for PHP when filter_var is not available (pre 5.2):