From Reed Olsen:
WallNotes is a simple application that allows you to place notes on your device's wallpaper. If you need to access information quickly, don't bother unlocking your phone and opening your notes application, just write it on your wallpaper!
Use WallNotes to: Make a custom background! Check your schedule! Store important notes! Make a reminder! Memorize a quote! Add text to a photo! Add your contact information in case your phone is lost!
The possibilities are...well, not quite endless, but close!
Store your notes on fun, built-in backgrounds like: a cork board, a sticky note, an old school computer terminal, and more! Check back regularly for more free themes! Have feedback or a suggestion? Hit me up on twitter: reedolsen