vBulletin is the best available forum software but it isn’t free. If you are a beginner and just want to start a forum, you may not want to pay a high license fee for vBulletin. What must you do then? I will suggest you forum software that are available for free and are nearly equal in quality with vBulletin.

The first forum software I want to talk about is SMF (Simple Machine Forum). This is open source free forum software available for free download from simplemachines.org. All the scripts are written in PHP and SQL database is used to store information. The software is completely customizable but removing copyright notice is beyond the terms and conditions you must agree to use a program. To give your forum a professional look, there are thousands of readymade SMF forums themes available. You can search for themes at SMF website or you may also use other websites which offer SMF themes for free.

The SMF software and updates are available for free download here:
http://download.simplemachines.org/

Second forum software I want to talk about is phpBB. In this forum, security is an issue. There are several reports showing security problems in phpBB. However, this is one of the best freely available open-source forum software. There are over 10,000 forums operated using this forum software. Like for SMF, themes can be downloaded and installed manually. The forum is customizable and works with PHP and SQL. A person with basic knowledge in PHP can customize this forum to make it function as they wish.

The phpBB software and updates are available for free download here:
http://www.phpbb.com/downloads/

These are two widely used free forum software. The software are updated on need base. I always recommend you to use the latest software version to keep you forum safe and well functioning.