The amazing Joanna Penn breaks down in detail the first 10,000 sales of her eboo, 'Pentecost'. Buy it here, by the way, it's a fun read and the cover is great (for the record, I bought her .epub version because I don't support DRM files). Articles like Joanna's are useful to all authors looking at the various options available to them to make some money from their writing, and because details on sales figures aren't very common, I think it is important to showcase them when they do appear.
Some points that stand out:
Over 98% of these sales were ebook sales on the Kindle
It is possible to make a full-time living as an indie author
Read the details of those headlines here: http://www.thecreativepenn.com/2011/08/22/10000-sales-pentecost/