I'm new to Drush; I managed to install it on a fresh installation of MAMP Pro in just a few minutes. However, installing Drupal is another matter:
$ drush dl drupal
Project drupal (7.14) downloaded to /path/to/drupal-7.14. [success]
Project drupal contains: [success]
- 3 profiles: testing, standard, minimal
- 4 themes: stark, seven, garland, bartik
- 47 modules: drupal_system_listing_incompatible_test, drupal_system_listing_compatible_test, user, update, trigger, translation, tracker,
toolbar, taxonomy, system, syslog, statistics, simpletest, shortcut, search, rdf, profile, poll, php, path, overlay, openid, node, menu, locale,
image, help, forum, filter, file, field_ui, text, options, number, list, field_sql_storage, field, dblog, dashboard, contextual, contact, comment,
color, book, blog, block, aggregator
$ drush site-install --db-url=mysql://admin:password@localhost/drupal --account-name=admin --account-pass=password
Bootstrap to phase 0. [0.01 sec, 3.71 MB] [bootstrap]
Drush bootstrap phase : _drush_bootstrap_drush() [0.05 sec, 3.93 MB] [bootstrap]