Well if what you're trying to do is to hide your IP address when you're on the internet then it's no going to work. Here's an excerpt from a nice description of IP spooing:
A common misconception is that "IP spoofing" can be used to hide your IP address while surfing the Internet, chatting on-line, sending e-mail, and so forth. This is generally not true. Forging the source IP address causes the responses to be misdirected, meaning you cannot create a normal network connection.
However, IP spoofing is an integral part of many network attacks that do not need to see responses (blind spoofing).
You're better off installing a personal firewall such as ZoneAlarm or installing a router if you're using broadband connection. If you get a router you can configure it so that it ignores pings so that hackers doing a ping-scan for IP targets to hack will not detect you. As for protecting your email from spammers- there are two approaches. One is prevention- don't put in an email address you don't want spammed onto any website. That's usually tough because eventually you'll inadvertently give out your email address and get spammed anyways. The other way is to use spam filters- check out programs like IHateSpam, MailWasher, SpamNet, and Spamnix.
