Killjoy - the 'code' for phishing mails or spam mails is just the mail text itself - plus meta data like country of origin, rDNS of origin IP, etc. It's just the malware where malicious code was used.
Of course the images in their current form don't have much practical use but the exercise is more art for the sake of PR/marketing than a scientific study. Interestingly, tests have shown that the algorithm used to determine shapes/textures/colours does produce similar forms for threats in the same family. The images aren't just dreamt up in other words. In one case an image was produced for some piggyback malware, the image came out along the lines of those above but with a parasitic looking blob attached to it's side.

The team along with the artist must have had a blast doing those images.

Just look at how the "keylogger" has it's "connections" to send data back to it's master, the "phishing spam" is very "hairy", to say the least and you can actually see the P2P subnets in the "Storm bot".

As someone who has had to deal with those problems, I find those images absolutely brilliant.

The color of friendship is blue. :P

You can take the code that makes a computer virus and run it into an imaging program that would make the images seen.

I vote the Vole's Office Assistants be used instead. They're all members of the dreaded lurgy and BSOD.

They bang in so often, I suspect they caught the acute grip from Ms. Dewey!

But only Larry knows for sure.
MS Bob's your uncle!)

..but questions like "what does a computer virus look like" make no sense at all!
You may as well ask "what's the colour of the concept of friendship?"
And what code is involved in a phishing link upon which to base a picture? 
On a less anal note, the pics look cool and more inspired by biology than technology.