group behind the PCI and PCI Express standards are busy working on the PCI Express 3.0 specifications and has already released some information about what we have to look forward to, in 2010.
The next generation of PCI Express will have twice the bandwidth of PCI Express 2.0, which isn't even out as yet, and the interconnect bandwidth should hit 8GT/s.
PCI Express 3.0 will be backwards compatible with previous version of PCI Express, which is good news in terms of upgrade options and costs.
The new standard won't be available until late 2009, but don't expect to see any retail products until 2010, that's three years from now, so PCI Express 2.0 has a pretty long way to go.
You can read the full press release here