WordPress integration to a site

Hello,

I am new to WordPress and BBpress. I have installed both packages on my local server. Now I need to integrate these two packages into one of my client’s site. Please help me with the following:

1. I need a single login screen and after logged in, users will redirect to a common Control Panel. Presently, the wordpress is available in the “wp-admin” and bbpress in “bb-admin” directories.

2. Need to register users from the non-wordpress based site. But I don’t how can I achieve the following:

[A] On registration time, store password in the user table. Please help to create the password with wordpress encrypion.

[B] How can compare the password with database password on login time?

3. Where can I find out WordPress Function References?

I hope that, the wordpress forum is active and will help me to start with WordPress.

Thank You.