I've been following this blog for quite some time now. It basically contains a list of all the latest plugin and sampler freebies. The blog is updated almost on a daily basis, and I have been led to many great free plugins from here:
http://bedroomproducersblog.com/
There are also lists of the top [insert plugin type here] plugins which may assist if you don't know where to start looking for the best free VSTs.
Anyway, thought I would share as it has been a great resource for me.
