I'm an absolutely huge fan of evernote and have been an avid user for a few years now. I've got it running on my imac, iPad, iPhone and Air (yes, yes, apple fanboy). Dont worry they cater for android too and even have a windows and web version as well.
I use it with a whole range of other services too, which allow me to cross post items into the software from over the place, including via email.
If you're anything like me and need to get things out of your head and onto paper in order to relax, then this is most definitely a service for you.
Oh and they even have a free version!