You can find where to take it here:
http://www.ets.org/portal/site/ets/menu ... f95190RCRD
I am not sure but I think that the last date was in may, it was just for the transition to the iBT version. It's been a chaos to register for the iBT and I live in Lisbon and had to fly to London to take the iBT can you believe it? Also I've heard that more schools in US are considering in accept the IELTS as proficiency test, currently Chicago, Cornell, Harvard, UC Berkeley and UCLA accept, perhaps some more schools.
If you know portuguese you can find info here:
The PBT version measures Reading and Listening, and I think that some grammar things, people use to say that it's way much easier than the iBT version. The problem with iBT is not that it is "that" hard, is just the speaking part, which is not only tough but also "weird". If you can have the PBT go for it.