This topic came up a few times on the listserver, so you might want to check there. Here is what response that I archived:
From: Randy Dawson [mailto:email@example.com]
Sent: Thursday, August 05, 2010 1:31 AM
To: Talk Mailing List
Subject: RE: Estimate layout time
Google this one:
Printed Circuit Board Layout Time Estimation
Cyrus Bazeghi and Jose Renau
University of California, Santa Cruz
Here is a suggestion so you can automate your necessary CAD library creation for the project at hand.
Register for the 10-day evaluation of LP Wizard and you'll get the license and download instructions the same day.
Install the LP Wizard program, open the component family from your datasheet, search to see if the library part exists. If so, click the LP Wizard button to create the CAD library part. If not, simply enter the correct component dimensions and click the Wizard button to create the library part.
You can create all 25 IC's, your FET's and resistors & capacitors in less then a day and your CAD library for your project will be 100% IPC-7351B compliant. It will also make your PCB layout look super professional (like you do this everyday).
Start your download process here: http://www.mentor.com/go/lpwizard
In the email for the download instructions is a link to "Getting Started User Guide" which will quickly teach you how to set up the LP Wizard program to be productive.
Don't remove the program after the 10-day evaluation trial. LP Wizard will run in "Demo Mode" without a license as LP Calculator. Try it, you'll like it.