Avoid Scam & Junk Sites

Many sites out there promise e-mails worth $50 and upwards. DO NOT join any of these sites as they are designed to take your money without ever giving you a penny in return.
Before you do anything, check out places like PTR Investigator which maintains a list of all these junk sites, and avoid them like the plague!. Use the PTR site to keep updated on potential new junk sites.

Avoid Spyware & Unwanted Software Installations
Some sites can install software silently in the background after you've visited them and you may not realize this until you have rebooted your computer. Avoiding Spyware is never 100% guaranteed, but there are a few things you can do to help yourself prevent this and other malicious software being installed on your machine. Here are some recommended things Windows users should have:

Use Mozilla Firefox instead of Internet Explorer

Internet Explorer is the biggest browser in the world, but it's also the weakest when it comes to avoiding these attacks, and until IE 7 is released to the general public, steer clear. The ideal is to use a tabbed browser, which will allow you to use several tabs within the same window, making browsing much more organized.
This browser has the capability to stop malicious websites installing software on your machine so is much less prone to getting caught out. It is tabbed and is customizable, so you can make it look more to your taste too.

Microsoft Anti-spyware
This is a tool from Microsoft that offers real-
time protection against websites trying to change things on your machine, as well as catching spyware before it is able to get itself a nest!
Microsoft will throw money at this until it's the biggest around. It's free, and definitely well worth having.

A Good Anti-Virus Software Package

* Something like Norton Antivirus or Macfee will help protect your computer. It’s worth the money to invest in a good one to keep your computer up to date and protected.