Here are some useful articles by a VC on Addressable Market Size:
Addressable Market
Making the Estimate
Is Your Addressable Market Size Realistic?
It is important to understand some of the terminology ... this blog site has some great definitions and a diagram:
TAM: Total Available Market – i.e. how big is the overall market?
SAM: Served Available Market – how much of that market is actually served by market participants?
TM: Target Market – how much will you reach within a given time frame (in diagram aove this is a called a Serviceable and Obtainable Market)
SAM: Served Available Market – how much of that market is actually served by market participants?
TM: Target Market – how much will you reach within a given time frame (in diagram aove this is a called a Serviceable and Obtainable Market)
Here is the methodology that Macromedia used to estimate Total Addressable Market Size for its products. Here is another example of calculating a TAM.
Some tips to learn how to develop revenue projections for your plan.
A VC's guide to startup market sizing from OVP.
And an excellent market sizing example from Lightspeed Ventures.