How to retrieve all addresses with non-zero balance and their balances? I'm looking for a way to retrieve all address balances of addresses with a non-zero balance in the blockchain.

Is there a software tool that can calculate the balances in an accessible format?
Or perhaps I can download them somewhere?

With an accessible format I mean that it can be interpreted by a computer. Either in a database-structure or in parseable text format.
This guy wanted to do the same thing. You can find a solution there.

in short:

get a Linux Box/VM with &gt;=8GB RAM
download blockparser
compile it
run &quot;./parser allBalances  -w 250000 &gt;allBalances.txt&quot;

the parser run take around 2 minutes on my vSphere VM (2x3Ghz Xeon, 16GB of RAM)
now you have a list of the top 250.000 adresses sorted by BTC amount.
add some sed/awk/cut magic to make a csv and you are done.