Most of the internet is written in English. There are web services like Google Translate that can translate non-English pages, but using them requires a distracting trip to Google.
To simplify the process, here is a bookmarklet that takes the current URL and sends it to Google Translate directly.
To create a bookmarklet for Firefox 3 that translates the current web-page from another language to english, create a bookmark and set the bookmark properties to the following values:
Google Translate - Prompt
Location (again, this time not encoded, although wordpress seems to maul the quotes and plusses this way):
Bookmarklet prompts for the source language of the currently-displayed web-page, and then sends it to google translate with the proper URL to tranlate it (to english). This bookmarklet is based on Google Translation bookmarklet from https://www.squarefree.com/bookmarklets/misc.html