Email feature in wordpress

Hi,

I have been trying to make the email feature work on my wordpress website. I just put up a Send Inquiry button and when the user sends me a message, I have an “autoresponder” mail message set up, that will be delivered to the user. Now I just tried it by entering my personal email ID and the auto responder mail landed up in my spam folder. Now I have some questions:

1. How do I prevent the emails sent from my website to users from landing in their spam folders?

2. I noticed that the autoresponder email had something like this in the “From ” label:

“<my company name> via gator4060.hostgator.com “

Why is it showing via gator4060.hostgator.com? Is this okay? Is this the reason my company’s mail landed in spam?

3. My email appears as simple text. Can I make it look more attractive using some simple HTML design code? If I did that, would it cause any problem and is there a possibility that the html code would be seen as spam by user’s email engine?

Any help would be greatly appreciated.

Thanks