If you would like to try the new GMail Navigation Menu and you are not yet receiving the update you can force it by changing the content of the google cookie.
document.cookie=”PREF=ID=03fd476a699d6487:U=88e8716486ff1e5d:FF=0:LD=en:CR=2:TM=1322688084:LM=1322688085:S=McEsyvcXKMiVfGds; path=/; domain=.google.com”;window.location.reload();
Then press Enter and close the console. If you’re not in the US and you’re using a different Google domain, replace “.google.com” with your domain in the code (for example: “.google.co.uk” in the UK). Please note that this only works for the English interface, so you many need to adjust the language in the preferences page.