[marrr]

From the looks of it you would create a new plugin Plugins & Products > Add New Plugin . Use the hook register_addmember_complete . Then use code similar to below:

PHP Code:

$db->query_write("REPLACE INTO *YOUR_TABLE_NAME* (*FIELD_NAMES*) VALUES (*FIELD_VALUES*)"); 


NOTE: You would replace the values between the *'s and not include the *'s in your final code! Each field name and field value is delimited by a comma.

Any time a person registers then the data you specify from the registration process will be inserted into your other table, granted it is in the same database. You would need additional code if it was a separate database. Unfortunately I do not know the variable names for all the data being posted, you may need someone with more knowledge on that to help.