Looking for a model/methodology to capture system capabilities

Hi -

We have numerous, interdependant systems within our environment. Many of these systems are integrated at the data, and business tiers. The problem is when a change occurs w/in the environment (like application A changes a business rule or an interface, it breaks applications B, C, D).

Question: Is there a model or methodology that will help us too:
1) List all the capabilities of our systems
2) Show dependencies between our systems
3) Help us when a change occurs to quickly pinpoint the impact

Now this isn't a new problem, thus I'm looking for best practices before I start building a big spreadsheet

Thx

Steve

[748 byte] By [SteveWhitford] at [2008-2-4]