Now-a-days we all have them. Tiny USB thumb drives which have replaced the floppy. Most computers don't even have a floppy drive any more and for good reason. Portable flash drives hold more, are more robust, and have come way down in price as flash memory gets cheaper to manufacture. Here is a list of free applications that will fit onto a flash drive:
1.) Portable Firefox 1.0.4
renders most sites exactly as it does when installed on your hard drive, but Java applets will run only if Java (which will work only if it finds settings already specified in the registry) is installed on the host machine.
2.) FileZilla 2.2.14b
For FTP and Secure FTP, FileZilla lets you choose between a secure mode that never stores passwords and a less-secure mode that stores passwords in an XML file on your thumb drive.
3.) Trillian Basic 3.1
The free Trillian Basic 3.1 instant messaging client works with AIM, ICQ, MSN, and Yahoo! Messenger, but it isn't designed to be run from a portable drive. The third-party Trillian Anywhere Web site provides simple instructions for setting up Trillian on your hard drive, creating all its settings, and then transferring it to a USB drive. The result is a trouble-free universal IM client that leaves no traces on the host computer.
4.) Open Office
The free open source office suite; you can choose between a stable 1.1.4 version and a faster and slicker 2.0 Alpha version. The 2.0 version fills 127MB, so you'll need a generous-size USB drive, but it guarantees you a full-featured productivity suite compatible with Microsoft Office wherever you plug in the drive. You may need to click through the license agreement on each new host machine, but that's a minimal inconvenience.
5.) XMPlay and CoolPlayer
XMPlay, a miniature but high-powered media player. It has the tiny, overelaborate interface typical of freeware media players, but with downloadable skins that can slightly improve it. Alternatively, consider CoolPlayer, a compact open-source MP3 player that can be extended via plug-ins to handle almost any current media format.
6.) AntiVir PersonalEdition Classic
A virus scanner, that checks the full range of viruses found in the wild which can be installed to your USB drive and run from any host computer.
7.) Avert Stinger
A reduced antivirus program that takes up less space and that focuses on a few high-risk attacks.
8.) Ad-Aware SE Personal Edition 1.06
A Powerful spyware remover. Install it in the normal way to your hard disk, then simply copy its folder to your USB drive.
9.) Windows CE
You don't need to carry a PDA to use the Windows CE operating system and its small-screen versions of IE and Windows Messenger. Just follow the instructions on Steve Makofsky's weblog to learn how to download Microsoft's free Windows CE emulator to your USB drive and use a batch file to launch the emulator and save its settings on the same drive. Make sure to read all the comments posted on the weblog to find essential modifications to the method described in the initial post.After you run the emulator for the first time, it restarts instantly with the browser or IM client already open and ready for action if you left them open earlier. You don't get an e-mail client or Firefox's powerful browsing, but nothing else on a USB drive gives you the same instant-on convenience, and you'll need only 32MB for the whole package.
10.) Damn Small Linux
based on the popular "live CD" Knoppix distribution, and includes Firefox, Thunderbird, and other open-source applications. All settings are stored inside the files used by the Linux system
You can find other USB compatible apps from many software manufactuers online. For a list of some of them, click here.