There are few applications that are just must-haves for me, but one that has become critical for me is Evernote. Its availability would impact what platform, mobile or PC, I would purchase. For those of you with a Blackberry that have been waiting for this app, the wait might be over.I say "might" because it is only available on a few devices, namely the Curve 8900 series, the Bold and the Storm. You need OS 4.6 or higher. Evernote is working on other models as well, and you may have a device that can be upgraded to a newer revision of the Blackberry OS.

Evernote is an app available for Windows, Mac OS X, Windows Mobile and the iPhone. There is also a limited web interface if your platform isn't specifically supported, but the native client is much better. Think of it as a long roll of paper, You just keep adding notes to it. The content is indexed on your PC and synchronized to a secure Evernote account. You can include text, pictures, voice recordings and more in your notes. The software is free, but there is a premium version that allows you to store any file in a note you want. You can access, search and add to your data from any PC with either a web browser or by installing the client on it. I use it on three machines and they all have a copy of my data.

Your phone can also access the data, though it doesn't maintain a local database, which is the only drawback. You can't really use Evernote on your phone when you are on a plane unless it is one of the few that has a WiFi connection. When on the ground though, using it with WiFi, 3G or even EDGE works well.

If you have one of the newer Blackberry's listed above, head over to the Blackberry App World and search for the app. The store should only show you what is available for your device, so if you see it, it should be compatible. The client is free and it should work just fine with a premium account if you have one.