Check out this Drupal bundle for TextMate. This thing is really, really helpful for writing modules! Especially when it comes to the infamous Form API!

On acko.net

Often times there will be troublesome characters in your HTML. This is especially true if you've copied text out of word processors, such as Micorsoft Word. The problem is that these trouble characters are not ASCII, and therefore don't display correctly in the browser. These special characters need to instead be escaped, rather than placed directly into HTML.