I replaced 2 new light fixtures in our hallway and when we put the circuit breaker back on, the lights are on and remain on. Wondering if the light switches might need to be replaced? Or maybe it's wired incorrectly?

Sounds like you have a miswired fixture. This site has a number of good diagrams that cover the different ways possible to wire a 3 way switch. Maybe one of these diagrams can help you figure out what is wrong: Installing A 3-way Switch With Wiring Diagrams - The Home Improvement Web Directory (http://www.the-home-improvement-web.com/information/how-to/three-way-switch.htm)

My guess would be that you have power through one of the lights and instead of sending the power through the switches and the lines from the switches to the fixtures, you simply have the power going directly to the fixtures.

If switches worked fine before changing fixtures, then you may have connected new fixtures to a constant live wire, instead of the switched wire. Any other wires in light fixture box?

Why did you replace the fixtures? Was there a problem you were trying to solve or just to improve the look?

To assist you further, I would need to know if you are using two switches to control both fixtures or 1 switch powering both fixtures.

It is entirely possible that you used a "White" from the switch loop to power the light all of the time.

Would you please describe the ceiling wiring and the switch loop as well as the connection to the second light.