Sorry that you had such a rough time in the forums. Asking for myspace passwords is a common request and invariably met with an unkind response. People don't like giving out trade secrets, I guess.

For someone in your situation, you have a few options:
*) if you have access to the other person's computer, you can install a keylogger. Even if you don't have access you could send one wrapped in a trojan program as an email attachment (there is always a way to get someone to open a suspicious file; never underestimate the power of social engineering). There are many keyloggers to choose from on the web, but finding one that won't be picked up by the Anti-Virus software will be hard.

2) brute force/hybrid attack. There are programs you can download or write that will constantly try different passwords until finding one that works. This could take a long time; on a site such as myspace, weeks possibly. Plus, you will need a way to get around the CAPTCHAs. And eventually, your program will start to look like a DOS attack on myspace's servers, the administrators of which will then call your ISP and have your internet turned off.

*) However, you know your adversary; might as well try to guess what the password is. If it doesn't work, that only took ten or fifteen minutes.

4) If you have physical access to this person's network (wireless or LAN) there are several programs you can use as packet sniffers to intercept the password. I personally like this method a lot, but it probably doesn't help you that much.

5) The "Professional" Method. Ok... this is a little tricky. People who hack myspace pages for a living use a phishing approach. It requires a shockwave file (which I do have a copy of, if you decide to do this), and a working web server. You embed this shockwave (FLA) file in a myspace page that you have access to—your own would work—and any one who visits it will be prompted with a fake login page, which is actually being sent from your server. This is a risky move, because that server will in some way trace back to you, whether you hired it from someone or if it is one you own. Plus, there is no guaranteed way to know that your target will fall for the fake page. There are ways to get around all of these problems, but it might be beyond the scope of what you are looking for. Still, this is the most popular and efficient method for mass password stealing, and myspace has certain "features" which make it very easy to pass off.

Again, don't let the rudeness get to you. And to clarify what was said in the forums: myspace passwords have nothing to do with hashes, and the program know as Cain would be completely useless. Except for the #5 and #2, retailiation by myspace.com is never going to happen. Even if they catch you doing something, the worst they will do is report it to your ISP. And retailiation from this guy's "hacker" friends is just as unlikely. Most of these methods can be made completely untraceable from a user's view. If they knew your IP address from some other means (anonymous LiveJournal posts display IPs, for example), then they might be able to pull something off, but the worst you could expect is that they might try to hack into your myspace account in return.

Sorry again about your myspace enemy. I know how that is. Please let me know if/when you get this message, or if you need help with anything else.

—Rylan