I went to an online web promotion site ("fill out this form and get a free something") and I got too far into the form before I realized what I was getting into so my e-mail address got grabbed by nefarious interests.
One result is that i have been getting a lot of spam.
Of course some are phishing expeditions of the type:
"log into you ebay/paypal/amazon account to confirm all your secret information stuff because you need to do this to keep the account open".
Fortunately these things are web pages and - although they contain referrals to the actual ebay/paypal/amazon links - the "where you submit the secret information" button is pointed to a fake site.
So i have been looking at the raw html code and looking at the fake site (with privoxy turned on) and then going to a reverse dns lookup (such as the one at dnsstuff.com and entering the URL numbers to track down the ISP that is hosting these fake pages.
Then I contact the ISP. I have flat rate long distance so I call them up because most of the ISP abuse contact information in WHOIS does not contain a valid abuse e-mail address.
So far in three cases out of three cases I have been the party who has alterted the ISP to the phishing site and they have canceled the account in minutes after I spoke with them.
So you can do something effective with only a little detective work and knowledge of internet tools. :-)