As neurons are more complicated than bits you can't measure the capacity of the human brain in terms of computer storage, but there are as many networked computers as neurons in the average brain [no it isn't, this is just a blog post, the fact that I think I read it somewhere is sufficient], so it is possible that networked processors could contain a brain.
The thing that made this blog post graduate from the draft list is this blog post from Matt Webb (who is writing about really, really interesting things at the moment) who links to a project called OpenWorm.
"The nematode worm Caenorhabditis elegans (C. elegans) is tiny and only has 302 neurons. These have been completely mapped and the OpenWorm project is working to build a complete simulation of the worm in software."That's a fascinating baby step to achieve the singularity. I suspect that the key thing to realistic life is getting the interfaces with the outside world working properly.