"Just click and type to add new tasks, set due dates or add notes, and (most satisfyingly) check them off as you're done."
"Copy your documents to your iPad, iPhone, or iPod Touch so you can take them with you anywhere. Documents are transferred safely and securely over USB using iTunes 9.1 (or later)." $1.99.
Sync your files online and across your computers automatically. It provides up to 2GB of storage for free and up to 100GB for paid accounts. Universal app. Free.