Depends exactly what you want.
There are several password managers out there which will carry the load for you, like Password pro, but if you wish to keep your own master list you could look for apps such as Stash which allow you to keep a private area on your iPad. One password to rule them all one...
I actually keep an encrypted list on an online service which I can access from any machine. Not perfect, but if they want the data that badly and put that much effort into getting it then they are welcome, as no financial details included
I ues an app called "Secure Files" Its great. Yoy get into in useing a password, you can store other things besides passwords also. Ex like photo's, there is a text editor, and you can import files from you home computer also. Its a pretty nice app.
I second the recommendation for Ascendo Datavault. I've been using it for years, never had a problem. Syncs flawlessly with the desktop version. Great features and they keep improving it.