For those that don't know, podcastalley.com doesn't require you to register on their site. All they require is a valid email address to confirm your vote at. And you can only vote once per month for each IP address you have. And only once per email address. PCA doesn't care what your IP address is for confirming the vote. You can use the same IP address to confirm the vote as often as you want.
Here's my ideas:
1. Proxies. Never used them for my votes but I'm sure they would work.
2. Wardriving. Drive all over town and hop on every unsecured wireless AP you can find.
3. Hidden frame. You make an iframe html tag in your website that gets thousands of visits per day. The hidden iframe will contain the voting form code from PCA. It will also contain a little piece of javascript that will auto-click the voting button for you. I used this method to push the votes up for a bunch of podcasts a few months ago. I found a baptist church podcast and pushed it up to the #3 spot in just a day. I also pushed a few random podcasts up in ranks, leaving comments at the same time that implied that each podcast was competitively cheating for votes.
All those ideas require you to have an unlimited number of email addresses. Which means you probably need to own a domain name and have a catch-all email account set up. Then you just make up random email address names on your domain.
Also, PCA banned anything from phonelosers.org from voting when I was screwing around with everyone's votes. So if you're really obvious about it, they will ban you.