How to be more interesting to prospective PhD advisors I've been in contact with a couple of professors at US universities recently, and both of them were interested in the projects that I proposed. Now, I will be applying to these universities this Fall, and I want to make sure that I make myself look interesting to these professors through our email correspondence. 

What should I do, through email, to make myself standout? What questions should I ask these professors even before I apply to their respective programs? Also, would it be appropriate to ask about financial support in their labs or departments at this stage?
You probably don't need to do much if they have already expressed interest. However, if you want to do more, read a few of their papers so that you are thoroughly familiar with what interests them. That should suggest at least a question or two. I think that questions are more useful to you than statements.

You can ask about funding, but the easiest question to ask is for who you should speak to about funding if not themselves. This lets them know you need it and also lets you contact whoever is responsible.