Simple block definition

/*
* Implements hook_block_info().
*/
function mysnippet_block_info() { //define a new block
  $blocks['mysnippet']['info'] = t('Basic Block');
  return $blocks;
}
 
/*
* Implements hook_block_view().
*/
function mysnippet_block_view($delta = '') { // define what to display
  switch ($delta) {
    case 'mysnippet':
      $block['subject'] = t('My title');
      $block['content'] = 'My custom block content'; // can off course be the return of a function...
      return $block;
  }
}