Just thought I'd share some of my inner circle wizardry experience with this kind of stuff. Linking an Excel or OpenOffice spreadsheet with a website would be very tricky. Fortunately, the kind and wonderous folks over at EVE-CENTRAL have build this beautiful API for querying market prices. You just type in this URL:
where "typeid" is the ID of the item you want to know about (in this case Tritanium), and it serves up this nice XML sheet with all the data for it. Look at http://eve-central.com/home/develop.html#xml
for more details on that.
To find the item ID of a specific item, you can look it up in the EVE static database dump. Or someone might have built a little tool for that already, not sure.
Now, trying to take this XML sheet and put the data into a spreadsheet automatically is the tricky part. Microsoft Excel has a tool built in for that, which you can read about here :http://office.microsoft.com/en-us/excel-help/get-external-data-from-a-web-page-HA010218472.aspx
. It explains how to query data from a web page and insert it into your spreadsheet.
So, although it'll take a little while for a programming n00b to figure out, it's perfectly doable. Just need some free time and a lot of dedication. Give that a shot, and let me know if you need any extra help.