The North American Soccer League has been given provisional status as the 2nd Tier of the US Soccer Pyramid. This makes it look like this
Top to bottom:
USL Premier Development League / National Premier Soccer League
US Adult Soccer Association / US Club Soccer
According to the press release, the NASL also looks to expand in the next couple of years, hopefully going from 8 teams to 10 by 2013.
Personally, I would love to see some teams from the USL Pro move up to the NASL. I can't help but wonder what MLS Commissioner Don Garber meant last night at the MLS Cup when talked about "simulated promotion and relegation". Maybe in the next couple of years the USSF will finally adopt a relegation system that would see teams move between tiers of the pyramid based on their performance. This system is used by pretty much every other professional league in the world. We'll keep an eye on the situation, but unfortunately it'll take years for such a huge change to come to fruition.