If you have a jailbroken iPhone or iPod Touch, you absolutely need to get iRemember now. It fixes the fact that Mobile Safari doesn’t save cookies, meaning that after you install it, Safari will remember your passwords. You have no idea how long I have wanted this.
Just add the iSpazio repo (http://repo.ispazio.net) to your sources list (in Installer.app), and then install iRemember. It can be uninstalled as soon as you install it, the change it makes is permanent. This app is a godsend.