I think it's mobileNotes, but I'm not at home to check on my comp. What I usually do is download a theme for the app I want to customize and see what someone smarter (or at least more ambitious ... lol) than me has done. Also there's downloads and / or threads for the complete stock iphone UI, wich I use ALL the time as a reference for folder / bundle names, and image names and sizes ... it's an awesome resource for theming.
If I was more ambitious (see above), I'd look it up for you, but if you check for my other posts, there are links in a couple of those.
Also I'll be updating one of my other posts over the weekend, on what pngs to change to have different index (note list), and details (actual note) pages ... which I finally got around to figuring out (on me own even ... used all my spare ambition on that ... lol).