See also how to hex a domain.

Mindworkshop has got some basic info on how to trace spammers.
One thing they got is how to trace spammers that has got a url looking weird, like http://3637542882 for example.
I made a javascript to calculate a url like that into a proper IP.

Some spam generators like to express their URLs as somewhat impenetrable-looking numbers, such as http://3637542882. This looks a bit daunting, as it's not a domain and it's not an IP address. At least, it doesn't seem to be one.

In fact, those long numbers are IP addresses – they're just expressed in a way intended to make them hard to work with. You can create one by treating the four sections of an IP address as four distinct numbers. The IP address for the Alchemy Mindworks web server, for example, is 216.208.127.226. Here's how to convert this address into a quasi-meaningless string of numbers: 216 × 16,777,216 + 208 × 65536 + 127 × 256 + 226

The formula is:

 A=floor (NUMBER/16,777,216)
 NUMBER=(NUMBER - (A * 16,777,216) )
 B=floor (NUMBER/65536)
 NUMBER=(NUMBER - (B * 65536  ) )
 C= floor (NUMBER/256)
 D=(NUMBER - (C * 65536  ) )
 

---