The migration from Joomla 1.0 to 3.x is a multi-step major migration. These 2 versions are a world apart and totally different systems. However you will still be able to migrate your content and your users to the latest Joomla versions.
As stated this will be done in 2 separate migrations: Joomla 1.0.15 Joomla 1.5.26Joomla 3.x (latest)
Download and upload this package from Joomlacode (you need to login to get it) to your domain and run the Joomla installer. Instead of "install example data" --> use "migrator script" and upload the script you got from your Joomla 1.0.xx site --> give the correct prefix as in your sql (probably 'jos_') , tick the "This script is a Joomla! 1.0 migration script" box and hit install
Next screen will show that (if all goes well) that the installation is successful. Follow the next steps and you are on Joomla 1.5! Make immediately a backup! Use the free Akeebabackup
We will be happy to assist you with your migration to Joomla 3.x. The fee for an upgrade or a migration depends on the size of the site. Get your quote for your upgrade or migration to the latest Joomla version!