Is it possible to give a public read only access to a Bitcoin account? Is it possible to give a public read only access to a Bitcoin account using the Bitcoin client?

For example if for an non-profit organisation it can be useful to have read only access to it's Bitcoin account.

I know it is possible to make an web-service that is displaying this kind of data, but this requires a third part authority.
If you want the person to see the balance of each address, give them an encrypted wallet used by you. This way they can see any transaction coming in, but they won't be able to spend anything. However, this requires them to run a Bitcoin client themselves, which can be a pain at times.
Use the Block Explorer and search for the single address you will be using. Case in point - all donations made to Wikileaks - http://blockexplorer.com/address/1HB5XMLmzFVj8ALj6mfBsbifRoD4miY36v (warning, this page can load for awhile).