I used to use an AccuGage made for Presta. Worked well.
http://www.ghmeiser.com/bicycle.htm
I have also used a Topeak Smarthead digital that was both Presta and Shrader. It leaked a lot of my air taking a reading in Presta mode, but it works very well taking a reading with a Shrader adapter threaded onto my tube. In other words, I use it in Shrader mode. This model gauge is no longer on the Topeak website, they now sell a different digital gauge that I have not used.
I usually use the gauge on my Silca floor pump for my bikes. But on the bike I have on my trainer, the pump that I use on that does not have a good gauge so I use the Topeak gauge.