I just found these Excel Financial templates at the Microsoft site via a link at del.icio.us.
I’ve only looked over them briefly, but there may be one or two that might be of use (some appear to be more for the U.S. market) – obviously, you won’t be able to replicate the sophistication of financial planning software such as Microsoft Money in Excel, but I find Excel useful for keeping track of earnings from affiliate schemes, especially when you’re having to do this across several sites and take into account exchange rates on some of them (such as with Google Adsense). These templates might be able to teach me better ways of doing this (through macros etc.)
A few example of the templates: