Rocky pointed me to an interesting announcement (first seen on Gamasutra, then expanded upon later) that Microsoft will be releasing a special "XNA Game Studio Express" - which from what I can gather is a rebranded version of Visual Studio Basic and DirectX bundled together. Their selling point is offering the "XNA Creators Club" for $99 - which sounds something akin to the Microsoft Developers Network (MSDN) for independent game developers.
Now, this would make sense if they allowed you to have an easy-to-use build and test environment for the 360. But instead it appears their way for copying code to the Xbox is uploading all your source and content to the KreatorsKlub, compiling for the 360, then obtaining it via Xbox Live. "Games developed using XNA Game Studio Express cannot be shared through a memory card at this time."
Rebranding Visual Studio, DirectX and an MSDN subscription as the "XNA Game Studio" is kind of a stretch... but hopefully it can lower the entry point of creating a development environment and let people focus on content creation earlier. And as any developer can attest to, establishing a build environment can be excruciating at best.
It is interesting, however, that GarageGames has started promoting its Torque engine for XNA. This can bring a serious producer of indie titles to the 360... and could definitely offer an interesting range of titles (and markets) to Xbox Live. If Microsoft would offer an easier way to test & prototype on the 360, they could see a huge influx of titles, and could easily become the indie hacker's platform of choice.