Pearl Izumi Mountain Bike Shoes

I'm looking for road cycling shoes. I currently own a pair of Pearl Izumi Mountain size 42. I looked on eBay to those two announcements:

Shimano Women Size 42
http://cgi.ebay.com/ws/eBayISAPI.dll?Vie ...

Diadora Women Size 42
http://cgi.ebay.com/ws/eBayISAPI.dll?Vie ...

The list Shimano says U.S. 9.5 and the Diadora said USA 10. Normally, I wear a size 9.

I looked European shoe size conversion charts and it's one that has different sizes of EU men and women and others who are the same for men and women.

All advice is appreciated.

You'll see some disparity between the calibration to mfg'r mfg'r as casual footwear. The shoes are something that you desperately need to get right. The best advice I can give you is to go to a bike shop and test the model closest to what you buy. The only way to get it is just to try them. There are nuances that you will not be able to identify otherwise, and they can make or break the fit. When you try them, you should be sure that the ball of the foot part of the contour of the shoe. You want a room toebox, enough to allow you to pedal without jamming your toe in the end (about half an inch). I recommend you try them yourself and limit the amount of time the employee that you consume. Buy tubes or something to compensate for the factor of consciousness.
Disclaimer: I absolutely recommend supporting the local bike shop. I would try to liquidation if you are limited by the budget.

The best thing to do is go to local bike shop and try them. Shoe sizes vary between manufacturers and you want a good fit. It costs a little more tp bring them to the shop, but it's worth it. Buy online pedals for the money itself.

Pay a couple extra dollars and buy in your local store, you can try, and they will help you put your cleats on correctly.