Open Source and EA meet and merge. The first one is obviously less cost and EA projects are spread across many man months with associated costs. Open source inherently conveys less cost or no cost. We have open source SOA tools for implementing SOA.
On Similar lines found some useful links from a linkedIn discussion group that recommends some commonly used EA tools to set up an EA practice. Archie Mate is familiar the others aren’t .
Open Source Tools for Enterprise Architecture
http://www.enterprise-architecture.org http://www.modelsphere.org/index.html http://archimatetool.com/ http://www.adoit-community.com