Reply to eeky (you're hellbanned): no, this does not make transactions anonymous, these are still pseudonymous. The difference is that you won't reveal your IP this way while using the client. Using the regular Bitcoin-Qt client with Tor has the same result. The novel thing here is that this uses the I2P network.
From what I know about i2p - there is no gateways to "outside" internet. As a result, this will work only with other i2p bitcoin clients, correct?
There are fewer gateways than Tor, but it will connect to the internet and function normally.
By the way, "outproxy" is the word for them. (In case others don't know)
Nodes can share the same blockchain within the I2P network and to the open Internet. If enough nodes do this, then the resulting blockchain will be the same in both networks.
Does this allow anonymous Bitcoin transactions, obviating the Zerocoin project?