The process for jailbreaking an iPhone manually is pretty involved; Apple's process of securing the iPhone and iPod Touch have made the barrier to entry for installing 3rd party applications on an iPhone much tougher. If you're looking to jailbreak your iPhone or iPod touch in the hopes of installing other applications or non-Apple-sanctioned ringtones, however, there are now some easier ways to do it.
First, iNdependence has been updated to perform the jailbreak for iPhones running firmware 1.1.1. So if you've got a Mac around, there's now a GUI tool to run your iPhone through the hoops to get it jailbroken. I'll post up a tool for Windows as soon as I see one, but for now it seems Windows users are stuck with the tough method; iBrickr hasn't been updated yet but remains the best hope for you.
Second, if you've got an iPod Touch, there's an automatic jailbreak tool that's available from iPod Touch Hacks that will do it all for you on both mac and windows. Both use the recent TIFF vulnerability.