bLADE Wiki is a free mobile personal wiki to let you take and manage your notes.
It runs on Windows desktops and Windows Mobile PDAs and smartphones - and can sync between them all.
It can even be run on Windows from a USB memory stick.
Either way, take your information with you - wherever you are!
It is a stand-alone application - that doesn't need or rely on a webserver. Files are stored locally with the wiki application. This means that using the wiki does not rely on network connectivity.
Why not use an online, hosted wiki? Because you're not always online. Particularly when mobile. For personal notes intended only for you, taking the notes with you (either on a USB stick or a mobile device) is just as effective. If you do need to share your wiki with others, the wiki data can be hosted on a shared directory for a more conventional collaborative wiki.