Coding in php can be a daunting and time consuming task. Before you start your next project you should consider optimizing your time with a php framework.
Using a framework is a great way to learn php, as well. Frameworks include features such as modules that are pre-built to perform tedious coding tasks and can help you learn better coding practice. There are many to choose from. I will go over some of the most popular ones.
1. http://www.zoopframework.com ZooP - Zoop has been around for a long time and is a great choice for either beginner or advanced users. It's biggest assets are that it is easy to learn and lightweight. ZooP allows you to easily use PEAR modules.
2. http://framework.zend.com/ Zend - This is a great choice if you are focusing on Web 2.0 types of applications. You can use APIs from Amazon, Google, Flickr and more. This framework has a massive following so you will be able to find plenty of help from the community.
3. http://www.seagullproject.org/ Seagull - Easy for any skill level. Great for beginners because there are a ton of pre-built apps that you can extend to suit your tastes or examine to see how they work. Experts love this framework because you can earn a cash reward if you offer an improvement to the code.
4. http://www.phpontrax.com/ PHP on TRAX - Based on Ruby on Rails. This framework has a strength in creating database-backed web apps which are based on the MVC structure. There are plenty of screencasts and demos available to help you get started.
5. http://www.horde.org/horde/ Horde - If you have been around for awhile you might recognize the name Horde from their fantastic webmail project. This framework was specifically designed to be localization-friendly.
6. http://www.phpfuse.net/ Fuse - This framework is based on CakePHP and Ruby on Rails. There are a bunch of features added to make this the most stable platform possible. Version 2.0 development is currently underway.
7. http://ez.no/ezcomponents eZ Components - A library of components geared toward specific tasks. If you have used ezPublish content management system then you may have seen some of the components in the library before.
8. http://www.cakephp.org/ CakePHP - A very popular framework that is easy for all levels of coders from beginner to expert. It has a strong focus on rapid deployment so it is a great way to save time.
9. http://www.agavi.org/ Agavi - Based on PHP 5 and forked off of the Mojavi project. Agavi's primary focus is on building full fledged applications, though it can also be used as a web site construction kit.
10. http://www.akelos.org/ Akelos - Great framework to be used on simple web servers. Has a strong community. Akelos is a PHP port of the Ruby on Rails framework and is for building web applications.
That should get you started! If you have been wanting to code in php but just not sure where to start then your questions have been answered. These frameworks will give you a big jump in the direction of accomplished php coder.