convert a town, state into a zip code

I need a link to an open source PHP function that will allow me to enter the name of a town, state and get the zip code. That I can then send the result to a PHP proximity function for the surrounding towns.

I am finding plenty of code to convert a zip code into a town but nothing to convert a town in to a zip code.

Can anyone help?
TIA
Dave

Just a thought... If you found the code to convert from zip to town, then why not reverse engineer the code to do what you need it to do?

As far as I know you have to buy that information.

In my city, it has 15 different zip codes more or less. So just having the city and state alone may not be enough information.

This question has been asked and answered many times according to Google. One link I found using the Google Maps API,

http://www.wearehathway.com/blog/tec...oogle-maps-api

Others:

https://www.google.com/search?q=api+to+find+zip+code

Perhaps I need to explain what I want to happen.
Background:
I like to go see/hear independent musicians sing. House concerts, listening rooms. church outreach, and any other venue.
Recently I was in Cedar Creek Texas at house concert. Cedar Creek is a small community outside of Austin. Early afternoon timing over about 5. Since I was withing 20 minutes of Austin and 2.5 hours of home, I ask around who was playing in Austin I might want to see. No one, either musician or patron could tell me anything.

What I would like to make available:
Musician log on, enter date, city, state, name, their URL, venue URL or Email.

Me: go to website, type in date, city.
I would get back a listing of all playing on that date within a 60 mile range. Would looks something like this.

Dec. 8, 2912 La Grange TX Marcia Ball http://marciaball.com/  http://www.thebugleboy.org/

I would already know the zip for La Grange because I could find it if I were to plug it in into a proximity function using my zip and a 100 mile radius. But what if I was going to Bloomington Indiana and wanted to be sure there were tickets available.

I would seem to that for to work is finding all the zip codes.

Originally Posted by corp769 Just a thought... If you found the code to convert from zip to town, then why not reverse engineer the code to do what you need it to do?

I've thought about that. My coding skills are not that strong. Though I may have to improve them.

http://developer.yahoo.com/geo/geoplanet/

I have found HTML code that uses the < form > tag and returned zip codes for the town. But it displays it on their website.
I need to examine the source code to their website and see if I can glean enough information to be useful and not not infringe on any copyrights.

<form name="form1" method="post" action="http://www.zip-codes.com/search.asp" target="_blank">
<table border="0" cellpadding="2" cellspacing="0">
<tr align="center"><td colspan="2"><b>Find ZIP Code of a City</b></td></tr>
<tr><td>Town/City:</td>
<td><input name="fld-city" type="text" size="15"></td></tr>
<tr><td>State:</td>
<td><input name="fld-state" type="text" size="5" maxlength="2"></td></tr>
<tr><td>&nbsp;</td>
<td><input type="submit" name="Submit" value="Search"></td></tr>
<tr align="center"><td colspan="2"><a href="http://www.zip-codes.com" target="_blank" title="Free ZIP Code Finder and ZIP Code Database">Provided by Zip-Codes.com </a></td>
</tr></table>
</form>