seanyboy
There are a couple commercial products available, which I can't speak to, but you can google them. Dude from fuckedcompany had one called junglescan or amazonscan, which was free and did a little graph for you. It's showing as down for a server upgrade, but it was supposed to be done in february, so it might be gone. You can capture the data yourself and do it up in excel. Amazon has a lot of funny business with the sales rank, it's not really science and the numbers come in sorta arbitrarily, but I usually find that the numbers at close of business on the US west coast are pretty realistic over the course of the day.

I'll ask around if there is another free one anywhere.

Authors depend on the sales rank alot to try to understand how their books are doing, BUT it is not the best metric and doesn't always represent what is going on in the flesh based world. Publishers pay for bookscan, which is run by Nielsen, that is a much better representation of sales life, but it costs big, the sample and extrapolate from sales in brick and mortar stores and amazon. I can run a bookscan for you if you like, send me the isbn and I'll see what I can pull.

Thanks Divine_Wino. I looked at a couple of these, but they didn't allow me to search the UK.
Thanks to Ruby and Google, I think I've got it cracked.

#!/usr/local/bin/ruby -w
require 'amazon/search'
include Amazon::Search
DEV_TOKEN  = "Yeah - right"    # your development token
req = Request.new(DEV_TOKEN)
search = ['asin_search', '0954828089', HEAVY, 'ASIN']
#search = ['asin_search', '0297851144', HEAVY, 'ASIN']

# parse the results of the search
response = req.send(*search)
# Print current sales rank

file   = File.open("c:\\gaia.txt", File::WRONLY|File::APPEND|File::CREAT)
file.print(Time.now.localtime.strftime("%Y-%m-%d,%H:%M"))
file.print(",0954828089,")
file.print( response.products.first.instance_variable_get("@sales_rank"))
file.print("\n")
file.close

Boy - it's hard to put preformatted text into metachat.

Well that looks like total gibberish to me, so it must work perfectly.