These are recommended, but not required.
For spelling:
http://www.google.com/toolbar/ie/index.html- if you don't have a built in spell check with your browser, many search engine toolbars have a spelling feature. The google toolbar seems to be the most used, though
http://dictionary.reference.com- a dictionary is sometimes a better tool than a spellcheck because you might find out you were thinking of the wrong word
For translation:
http://www.freetranslation.com- probably not the most accurate translator out there, but it does a fairly decent job.
more items might be added later on, depending on what is found.