Is there any extension to hide product prices and disable checking for unregistered users?
Instructions on how to change yourself:
http://www.magentocommerce.com/boards/viewthread/22673/
Look for instructions sent by szotyi about halfway down. He does a good job to guide you through the process.
Or, you can buy:
http://www.magentocommerce.com/magento-connect/bolasevich/extension/2096/hide-product-price-for-non-registered-users
Finally, it is even more expensive:
http://www.magentocommerce.com/magento-connect/Cart2Quote/extension/5905/not2order_hide_price_disable_ordering
Our B2B module also supports this feature and a few more: https://github.com/sitewards/B2BProfessional
I think you're looking for this http://www.magikcommerce.com/magento-hide-price-extension The Magento extension, which hides product prices, allows you to call up price functionality, and even lets you customize various other options.