There are a few nice options for securing your passwords on your desktop computer and for your iPhone/iPod Touch. A few of the nicer options sync the two together.
1Password is has been able to create a rather robust solution for both environments and do it within a pleasing user interface. Making it very popular amongst many folks.
An email just came in saying that the Agile Web Solutions team has been working on mock ups of how 1Password will look on the iPad. So much more room and the option for landscape view means a much more desktop like interface.
Here is a couple little views, jump over to their site for the full size images: