On your magento powered website you will notice the following bar on the bottom of your product catalog
So you can see from this this page is set to show 16 items per page
To increase this and drop the amount of pages your products are spread over you need to follow these steps:-
1) Log into your Magento Admin Panel
2) In the top navigation bar select "System" and "Configuration" as pictured below
3) Then in the new window which opens under the Catalog section in the left side select the first option "Catalog".
4) Then you need to address 2 of these fields as shown below - "Allowed Values" and "Default Value". The allowed values are a list of values that appear as options in the drop down menu on the website frontend when being used. Your default value dictates which value is loaded as default and as such your desired value must be in this list so if it is not you can add it following the same format as currently entered values i.e. if you wanted the website to show 12 items you would have allowed values to "8, 12, 16, 32" and Default value to "12".
After you have completed your fields you need to click "Save Config" in the top right hand corner and your changes will be effective immediately