Excellent, thanks for your explanations Deafboy and marcus_of_augustus. I'm going to install Tor and try this for myself.
A GUI would be interesting, indeed, to allow easy registration of domains, alias, etc.
A GUI would be nice, but I was thinking of a simple function that would work something like this:
Please enter the name of the alias: bitinvestor
Do you want to add a Bitcoin address (y/n): y
Please enter the address: 12GDjkEWCK7DY6316igF9omUQPtxQ5jd5V
Do you want to add a Namecoin address (y/n): y
Please enter the address: NDqxkdTDCJtGE2WZg2HBcpMU7XPDWt4LXQ
Do you want to add an e-mail address (y/n): n
Do you want to add a phone number (y/n): n
The cost will be 0.1 NMC. Do you want to create the alias (y/n): y
The alias has been created and can be accessed in 12 blocks.
This would be sufficient for most people and if somebody needs to put something else in there then he can do it manually.