I do love caller ID, because it lets me avoid the telemarketers.
When I was doing cakes people would call me all day with inquiries, and I had a little system set up to handle them and to set up appointments. I tended to not answer the phone at all if I was working, but if I did I had a little intake form to fill out as I spoke to the bride. It included the basic information that I would need, and I made sure to fill that out completely. I also had my cake schedule right next to the phone so that I could check on availability before I started filling out the form.
If you hate talking on the phone, or you feel that you need time to work up quotes before getting back to people, you can always leave a message that sends people to your website to fill out your contact form. A message like "Sorry we can't take your call right now, we're working on cakes for other customers. To get a quote or receive more information, please fill out the contact form on our website at www.buymycakes.com and we'll get back to you within 24 hours." If they leave a phone message anyway, you can call them back to get the information, and tell them that you'll email a quote back. It's better to have everything in writing, so emails are better than phone messages.
If you're really phone-averse you could go so far as to leave a message that says that the inbox isn't checked more than a few times a week, and if they want a quicker response they should use the website form.
If you want to be totally hardcore, don't put your phone number on your website! Offer your email address and your contact form as the only options to get in touch with you. This is risky because some people still don't like doing business online. There are plenty of online businesses who don't have their phone numbers listed, though, so it's up to you. I personally wouldn't totally eliminate the phone, because sometimes people need to call you directly for whatever reason.
The best way to handle phone-aversion is to have all of your forms ready to go right next to the phone, and to give yourself time to get back to people with price quotes. Don't feel that you have to give them a price during the phone call, that rarely works out well. Give yourself some time, figure out the details, and email it back to them to take the conversation online.
Kara Buntin owns A Cake To Remember LLC, online cake supplies at www.acaketoremember.com and www.acaketoremember.etsy.com