How to convert Windows applications into Portable (pseudo) applications?

Hi All,
I just found a very helpful article on using normal programs like any other portable applications.
Before that lets have some basics cleared.

What is a Portable Application?
Simply put "A portable application is a computer program that you can carry around with you on a portable device and use on any Windows computer."

From wikipedia "A portable application, or portable app for short, is a software program that does not require any kind of formal "installation" onto a computer's permanent storage device to be executed, and can be stored on a removable storage device such as a USB flash drive and used on multiple computers."

For examples: see Wikipedia

A portable application does not have to be installed on a Windows computer to be used. It can be used directly from the portable media (like USB flash drive) you are using. Without the hassle of installing on every machine, you can carry your favourite applications with you and start using them with a single click.

What are the advantages of Portable application?

*Speed. If you have an app, like an email program, which saves significant amounts of data, performance will be much better on a hard disk. Writing to flash memory is much slower, by several orders of magnitude.

*No Footprint. Due to the use of the registry and system DLLs, regular apps can only be installed using an installation program. Installing and uninstalling "portable" apps is simple and straightforward, and doesn't make your system any more complex and tangled than it already is. Also, many traditional programs require administrative rights to install, which is generally not the case with portable apps.[my favorite]

*Portability. Even though the program is stored on a hard disk, if you want to move it (and its accompanying data) to another computer, you can just copy the directory in which the app resides. Because it doesn't use the registry, everything necessary to run that program can be easily moved.

*No worry.You don't have to worry about the programs screwing with the registry or dumping crud in \windows\, you can delete them entirely just by selecting their directory and pressing delete, and if you reinstall windows they're ready to go, no reinstallation necessary. If you want to use them on a different computer, whether permanently or just via a network share, no problem.

*Clean.They keep their configuration information in a file instead of the Windows system registry.This defnitely speeds up your system.[In fact, what is the justification for putting all the mundane settings in the registry? I can't think of one.]

*Privacy. You can use TrueCrypt to encrypt your USB drive. This will keep your email, browser history, etc. private while still using computers in various locations. It's nice to be able to let Firefox always save logins and passwords and know they'll stay private.

You can find the list of portable applications in my earlier blog. Seeing the extensive list you understand the scope of these apps. There are plans to include portable Operating systems in future!!