I recommend doing the same thing for web development.

There is a nice Firefox plugin (Firefox Throttle) that lets you throttle uploads and downloads with a single button click. If, like most web developers, you do development on localhost using the plugin lets you see how your user's experience uploading large files or downloading image rich pages with network latency.

Unfortunately its been pulled from the addons library search but you can download it directly (for now) using the ftp url in the comments here:

http://support.mozilla.com/en-US/questions/755876#answer-107...