if (og_is_member('node', $current_group->nid , 'user', $account)) {

Seems that lates og_is_member needs 4 parametars when checking if user is part of the group, not 3 like it is written in most posts online, so you can get it like above.

If you are using FB connect module and its Invite friends submodule or making your own invite FB friends submodule (which is easy). You could probably get into a problem of having no notifications sent to user when you do click Invite in FB dialog box.

Views has many options. You can change styling and structure of rows of data in interface of with templates. When I first started using views I choose templates, partly also because of not so much power in UI, but now you can do almost anything with UI. But after using UI, I would still recommend templates.

This has been a long wish for me. Sync databases online and on localhost.

There is an add on for drush that does that
https://drupal.org/project/drush_sql_sync_pipe

After using views slideshow and jCarousel (and not so happy the way they work, mostly in theming department) there are new players in town and they are even responsive. Also easy to theme and easy to setup.

I had a form without this "name" parametar, and without that parametar there is just no file object in validate function for file upload

To delete/edit selected rows from tableselect and have something to work in in form_state you should add keys to your array in your form like:

Setting a session in Drupal is easy, everything is set from the Drupal boostrap, all you need to do is to set it and get it. Like

$_SESSION['zip'] = $form_state['values']['zip_code'];
and latter you just get value on some page like
$view_filters['field_zip_range']['value'] = $_SESSION['zip'];

function custom_views_pre_view(&$view) {
    if ($view->name === 'pricing') {
  $view_filters = $view->display_handler->get_option('filters');
    $view_filters['field_zip_range']['value'] =  $_SESSION['zip_code'];
   
  $overrides = array();
  $overrides['filters'] = $view_filters;
  foreach ($overrides as $option => $definition) {

You can alter views, alter queries and much more. Problem with documentation online is that is lacking some crucial information.