It appears ethereum is using plain hexadecimal addresses like
0x0092e965928626f8880629cec353d3fd7ca5974f for now.
I noticed, the ethereum C++ implementation outputs so called ICAP addresses, check this generated by
> ethkey new test Enter a passphrase with which to secure this account (or nothing to use the master passphrase): Please confirm the passphrase by entering it again: Enter a hint to help you remember this passphrase: 321 backwards Created key 055dde03-47ff-dded-8950-0fe39b1fa101 Name: test Password hint: 321 backwards ICAP: XE472EVKU3CGMJF2YQ0J9RO1Y90BC0LDFZ Raw hex: 0092e965928626f8880629cec353d3fd7ca5974f
What is an ICAP address? Are these to be used in future releases like we are used to in Bitcoin? Do they always start with X? Do they have a checksum?