Solution 1:

A Beginner's Guide to mod_rewrite.

Typically this will be nothing more than enabling the mod_rewrite module (you likely already have it enabled with your host), and then adding a .htaccess file into your web-directory. Once you've done that, you are only a few lines away from being done. The tutorial linked above will take care of you.

Just for fun, here's a Kohana .htaccess file for rewriting:

# Turn on URL rewriting
RewriteEngine On

# Installation directory
RewriteBase /rootDir/

# Protect application and system files from being viewed
RewriteRule ^(application|modules|system) - [F,L]

# Allow any files or directories that exist to be displayed directly
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

# Rewrite all other URLs to index.php/
RewriteRule .* index.php/$0 [PT,L]

What this will do is take all requests and channel them through the index.php file. So if you visited www.examplesite.com/subjects/php, you may actually be visiting www.examplesite.com/index.php?a=subjects&b=php.

If you find these URLs attractive, I would encourage you to go one step further and check out the MVC Framework (Model, View, Controller). It essentially allows you to treat your website like a group of functions:

www.mysite.com/jokes

public function jokes ($page = 1) {
  # Show Joke Page (Defaults to page 1)
}

Or, www.mysite.com/jokes/2

public function jokes ($page = 1) {
  # Show Page 2 of Jokes (Page 2 because of our different URL)
}

Notice how the first forward slash calls a function, and all that follow fill up the parameters of that function. It's really very nice, and make web-development much more fun!

Solution 2:

You cannot do this with PHP alone. You'll need to look into mod_rewrite (assuming you are using apache).

Solution 3:

Using mod rewrite:

RewriteRule ^videos/play/([0-9]+)/([^.]+)$ play.php?id=$1&name=$2

example.com/play.php?id=203&name=google-io-2009-wave-intro

would work as

example.com/videos/play/203/google-io-2009-wave-intro