You may or may not know it, but Wireshark (www.wireshark.org) also comes as a portable version that you can install on a USB flash drive. I did a tutorial video on how to install it on a USB flash drive. I also show how to link NetScanTools Pro 11 to Wireshark so that you can launch Wireshark from within NetScanTools Pro. Pretty cool. They can both live on the USB and be fully portable, no installation required.
It's on youtube and will be on the videos section of netscantools.com soon.