I want to replace the new topic form with a custom form that has several input fields other than just the $postText. I want those fields to be output in the post where $postText is now. Any ideas on how to get started on this?

Try to look at templates/main_post_form.html variable. Probably, this is the file you need to edit and add your new fields. Don't forget that you also need to parse these fields on input; use handlers in bb_plugins.php.

Thanks. But I want this to be a custom form that is different from the main_post_form. So in other words, one form for new topics and the current one for replies. Unfortunately it appears that main_post_form serves both functions now. Any thoughts on how to change this or if anyone else has tried something similar?

Scratch that last post - I figured out how to do it using the 1st page & separate topic form addon. But I am having trouble parsing the new form elements when they come in - how do I do that?

What do you mean exactly by "having trouble"?

Sorry, let me re-phrase: I am able to have a custom form with an additional field called "var1". I am able to display the "var1" field on the form and manipulate the code so that the value in the form gets inserted into a new column in the _posts table. But I am having trouble getting that new "var1" column to display in the post itself. Guessing I have somehow use the db_simpleSelect function?

Take a look at some of our addons (Avatars, for example), and you will notice here is a function called parseMessage(). You can use this function for parsing addional message results.

Alternatively, if you want to destroy the core, edit bb_func_vthread.php file and paste additional fields in DB request. Assign them to variables like any others, and paste them as variables into main_posts_cell.html template. This will display fields in the thread listing.