Just passed the N10-004 this morning with an 873/900
The test is very simple, have no worries. Just go through all of the objectives on the CompTIA Network+ 2009 pdf, and once you have a firm understanding of them all, you will be fine.
My knowledge: Been working in IT for at least 8 years as a freelancer. Been working in an actual IT related job for about 10 months of that time.
But really, a firm understanding of the objectives will do it for you. It was nice to see how basic and simple some of the questions were. I reviewed with the CBTNuggets Network+ 2009 videos. Michael does a really good job in those videos, going through all of the objectives. He goes more in depth than the needed, but that's a good thing. If you feel confident after watching those videos, go for it.
I was really stressing about this test, and when I got in there and started answering a few questions... the stress all went away. Definitely know your objectives though, don't pass on any of them. If you have any questions I'd be happy to help!