both languages have their benefits. PHP would be slightly easier to learn, if you have learnt Java ASP.NET is quite, but not entirely similar in the fact that there is object oriented programming with the use of classes. Companies that usually use PHP are small to medium sized, whereas bigger companies or multi-national companies tend to use languages like ASP.NET as it is supposedly more stable and they have to pay for its platform more than that for PHP
Good places to start learning about this would be
www.hotscripts.com and
www.w3schools.com
