Multisignature adoption has to follow a multi-step process:
1. A majority of miners have to put multisignature transactions into blocks so they get confirmed.
2. A significant fraction of everybody else has to relay multisignature transactions so they reliably get to the miners (preferably more than 50%).
3. Depending on what you're using multisig FOR (escrow? secure wallets?), more technical infrastructure will need to be built.
4. After all of the above is done... y'all will be able to reliably use multisignature transactions.
April 1'st was the first step and we're doing pretty well with the second step, version 0.6 has a lot of support on the network already. In fact, it is going so well I think we should turn on the 'addmultisigaddress' JSON-RPC method so people can start creating and experimenting with multisig with the 0.6.1 release.