I fully intend to put together a writing tutorial or two someday, but at the moment I don't have one. There are, however, some other bits and pieces worth looking into if you're a writer...
This is a great free Word Processor, that I use personally. It's compatable with a wide variety of formats, including .doc, so you can open most other Microsoft Word documents in it. I prefer it because it's easy to get ahold of, and isn't made by Microsoft (and therefore not inherently buggy)
This is an interesting utility by Google (handy if you already have gmail/a google account). Basically it's an online wordprocessor that you can write in or upload documents to (it accepts a lot of formats). It's great because you can share the documents in question with other people, allowing them to collaborate (i.e. edit, add, correct, etc.) or view what you've written. Great for anyone doing collaberative pieces.
A great resource for any writer; a database of names by country, with meanings and etymologies. A lot of writers, myself included, have trouble naming characters off the top of their head, and this is great if you want to give some meaning and theme to your names (like, say, giving an aristocratic family all classical Italian names or something like that). Worth keeping in your bookmarks if you ask me.
Really, any online dictionary will do (I know some people use websters), but this is the one I use simply because it's easy to remember, and has spelling variations (i.e. it will return an entry for Colour as well as Color), and has a partner Thesaurus.com. Anyway, an online dictionary is a good thing for a writer to keep handy, because a lot of word processors will have less than perfect dictionaries, meaning if you need to double-check a word (or try and find the spelling of a word you only know how to pronounce), these'll come in handy. A thesaurus is also good for adding variety to your descriptions, but don't make the schoolboy error of just throwing any big word in.
Kaileigh Blue has produced a List of writing clichès, written in a rather satirical manner.