Vega is GUI-based and runs on Linux, Mac OS X and Windows. It’s written in Java and based on the Eclipse RCP framework. The core of Vega is its automated scanner and intercepting proxy.
Vega also includes an intercepting proxy. The proxy is situated between a browser and the target application, intercepting all requests and responses between them. Users can view the interaction of the client with the website, intercepting and modifying requests and responses to probe and verify possible vulnerabilities. The proxy is also capable of intercepting HTTPS communications with dynamically generated man-in-the-middle certificates.
Users can also write their own modules on top of Vega and extend it significantly.
You can read more on SubGraph’s blog: http://keystream.subgraph.com/2011/07/01/vega-beta-release/.