SaaS, SOA , Software + Services

The above terms are something that you will hear on a regular basis these days. I am going to go on a hunt. A hunt to find out what are these terms, what do they mean, and what impact do they have on the industry in the coming years. This is going to involve some amount of research so I will be updating this on a regular basis.
Till then ... time for a treasure hunt!

Update on 27 Mar 08
Found this image on the architecture journal article
http://msdn2.microsoft.com/en-us/arcjournal/bb906061.aspx

It gives a nice picture.




So far what I have think is
Software + Services is a Microsoft initiative. Talks about Software + cloud serices. I need to find out what is this cloud services.
SaaS is basically some applications that are ready to be used and are consumed over the internet. Now how is this different from WS..?
finding out...