Guys, I am planning a road trip to Broken Hill in April. Is there anything that we should see on the way? I wouldnt mind stopping somewhere for one night to stretch the legs.

You forgot to say where you are starting from.

If you are not Australian, note that April will still be quite hot - up to 40 degrees celsius or so. It could be cool - the outback is like that. Broken Hill is also remote and as such you need to be prepared. You will be driving through lots of "nothing" we love it but lots don't. I assume you know it is 1300km and a 14 hour drive.

The Menindee Lakes and Lake Mungo would be well worth a visit.
Broken Hill is full of Art Galleries.
There's a Big Beer Can at Cobar.
Parkes has the radio telescopes that recorded the moon landing.
Bathurst has gold rush history.
Dubbo has an open plains zoo that is reportedly very good.
Nyngan is about halfway:
http://www.visitnsw.com/town/Nyngan.aspx

Any particular reason why you are going there?
Have you been Outback before?

Sorry magda, where you were starting from was in the title. I was only looking at the body of your message.

After all that, can't help in relation to starting from Sydney.
I agree with Peter that Lake Mungo is interesting but it is still a pretty good drive further past Broken Hill.

Have you considered the train to Broken Hill? We just did Sydney to Perth on the Indian Pacific Railway, and it stopped at Broken Hill. Left Sydney about 3 Saturday afternoon and arrived BH next morning.
http://www.gsr.com.au/site/home.jsp