fulcrm_apiv2/fulcrm_apiv2.admin.inc

<?php

function fulcrm_apiv2_admin_form_submit( $form, &$form_state ) {
    variable_set( 'fulcrm_apiv2_hostname', $form_state[ 'values' ][ 'hostname' ] );
    variable_set( 'fulcrm_apiv2_user', $form_state[ 'values' ][ 'apiuser' ] );
    variable_set( 'fulcrm_apiv2_key', $form_state[ 'values' ][ 'apikey' ] );
    variable_set( 'fulcrm_apiv2_client_id', $form_state[ 'values' ][ 'clientid' ] );
}

function fulcrm_apiv2_admin_form( $form, &$form_state ) {
    $form[ 'title' ] = array( '#type' => 'item',
                              '#title' => 'fulcrm APIv2 Settings',
                              '#description' => '',
                              );

    $form[ 'api' ] = array( '#type' => 'fieldset',
                            '#title' => 'fulcrm.org APIv2 Credentials',
                            );

    $form[ 'api' ][ 'hostname' ] = array( '#type' => 'select',
                                          '#title' => 'Instance',
                                          '#description' => 'fulcrm.org APIv2 instance',
                                          '#options' => array( 'fulcrm.org' => 'LIVE',
                                                               'test.fulcrm.org' => 'TEST (live data, pre-production code)',
                                                               'dev.fulcrm.org' => 'DEV (test data, in-development code)',
                                                               ),
                                          '#default_value' => variable_get( 'fulcrm_apiv2_hostname', 'fulcrm.org' ),
                                          );
    $form[ 'api' ][ 'apiuser' ] = array( '#type' => 'textfield',
                                         '#title' => 'API Username',
                                         '#description' => 'fulcrm.org APIv2 username',
                                         '#default_value' => variable_get( 'fulcrm_apiv2_user', '' ),
                                         );
    $form[ 'api' ][ 'apikey' ] = array( '#type' => 'textfield',
                                        '#title' => 'API Key',
                                        '#description' => 'fulcrm.org APIv2 key',
                                        '#default_value' => variable_get( 'fulcrm_apiv2_key', '' ),
                                        );
    $form[ 'api' ][ 'clientid' ] = array( '#type' => 'textfield',
                                          '#title' => 'Client ID',
                                          '#description' => 'fulcrm.org APIv2 client ID',
                                          '#default_value' => variable_get( 'fulcrm_apiv2_client_id', '' ),
                                          );

    $form[ 'actions' ] = array( '#type' => 'actions' );
    $form[ 'actions' ][ 'save' ] = array( '#type' => 'submit',
                                          '#value' => t('Save'),
                                          '#submit' => array( 'fulcrm_apiv2_admin_form_submit' ),
                                          );
    return $form;
}

function fulcrm_apiv2_admin() {
    return drupal_get_form( 'fulcrm_apiv2_admin_form' );
}