I liked this person's reasoning at Slashdot.com regarding changing his friends and family from Internet Explorer to Firefox. The writer said he was being somewhat flip, but I think he makes some good points.
For the whole thread, one regarding someone's question about whether he should bother telling his grandpa to change over from IE to Firefox, see http://ask.slashdot.org/article.pl?sid=04/12/17/191225&tid=95&tid=113&tid=154&tid=4
Quoting:
This is why when the issue comes up with people I know I tell them this:
"You can do what you want, but I recomend you use firefox, if you continue to use IE I will refuse to help you when your computer gets infected with viruses"
That said, everyone that I have had try firefox has loved it and begun using it exclusivly. Normally I just say "here let me do some setup for you", install firefox, take ie off the desktop and the start menu, and then explain the new web browser to them. Often I just tell them "I upgraded your web browser, its called firefox now"
I know to you or I this sounds very deceptive, but I realised something: its just abstraction. Forget the details of code base and who puts it out. I believe firefox is a better browser, these people don't even know what a "web browser" is. Thats why its called "The Internet" on the desktop shortcut and not "IE" - because "IE" or "firefox" is more detail than most people want.
If you try to tell them "I installed firefox, this is what to use now because ie is bad", then you have a few problems.
1. They don't know what you are talking about anyway so they are scared.
This means they worry "oh God is this going to be harder to use?" You can try to tell them its not, but they wont believe you because they saw you do all these weird things and so they know your idea of easy and theirs is way different.
2. They may have used ie before and so far as they are concerned it is great. So when you say "its bad" (or however else you want to qualify or expound upon that) it doesn't jive with their experience, so they assume its just stuff they don't need to care about, or you are just being esoteric...they go back to point 1 and figure this is going to make their life harder for benefits that mean nothing to them anyway.
So all in all, you save both your you alot of trouble by abstracting away "firefox" and "ie" and just going to "I upgraded your web browser" and when they say "whats that?" you say "Your internet is better and more secure."
To learn more about Mozilla Firefox, see http://mozilla.org
The Mozilla Thunderbird e-mail program is also there.