Pgpool was born in 2003. When it was reborn as pgpool-II in 2007, we had made a big change of its architecture. For example, we gave a capability to pgpool to use more than 2 DB nodes.
In 2010, we are refactoring pgpool-II again: disentangling the spaghetti code(there are tones of global variables, which is a bad sign), moving some codes from a file to more appropriate one and so on. I believe the work will make pgpool-II more solid, easier to understand by new developers.
Of course we are not just refactoring pgpool-II. We will add nice features including adaption for Streaming replication/Hot Standby, which is one of the greatest features of upcoming PostgreSQL 9.0.
We hope the work will be finished by August.