How to add a user profile field when installing a plugin

[Analogpoint]

Thanks for the answer Reeve.

Hard coding the fieldname makes sense.... If I add the field to the user or userfield tables during the installation of the product/plugin, how can I add the additional information such as the title and description/instructions that appear by the field when the user is looking at their profile?

What this is for is simply a plugin/product that adds a field to the user profile (the users fill it in) and the plugin automatically modifies the postbit to add that field to be displayed. You can do the same thing by adding a custom user field manually and modifying the template. I just want to automate the process by providing a product/plugin to do it all in one shot.

Thanks.