Everything you need to know about manuscript formatting is here. Allegedly.
There’s so much conflicting information around that it’s hard to be sure exactly what publishers and agents want (my agent was pretty flexible Courier or Times were both fine but the font size was important) but it’s an interesting read, and nicely laid out.
Donna Andrews rambles on about formatting on the Lipstick Chronicles, and gives some useful tips.
An article on Zarina Docken’s blog gives an interesting comparison between different ways of estimating word count.
It’s important to know that not all word counts are equal. MS Office and Openoffice, for example, give different counts for the same text. It depends to some extent on the formatting, and punctuation.