TOPIC:

Why don't you check out this link www.library.illinois.edu/ugl/howdoi/secondarysources.html. Just run a general search on the net and you'll be able to find many documents discussing the various secondary sources available online.

Where can I find secondary resources on the web?

I agree. But just to add a little bit more, narrowing down a topic means you break the main topic into sections. Or in other words, you break it into keywords.
Once you narrow down your topic you can identify keywords in your topic and search them using a search engine - such as Goggle or Yahoo.

There are lots of sites providing information on history related information. However, to do a proper search you need to narrow down your topic. What is the history related topic you are working on? Is it about a particular time period, a battle that took place or way of life etc

The more you specify your topic, the more detailed information you can hunt down.

I'm working on a presentation on a history related topic. Any suggestions where I should look for secondary sources on history topics?