I need help with using ubuntu?

im a new user to ubuntu ive just recently loaded a copy of ubuntu 7.04 on my Packard bell laptop mx67 (intel core II, 1gb ram, 120GB hdd ) and i get a high pitched noise (soundmax digital audio hd drivers) how do i solve this? and also how do i go about installing programs o the system? i want to install firefox 3 beta 5 .. i know that ubuntu 8.04 comes with that and ive ordered my cop, but i want to get a more intimate knowledge of the operating system and working with the terminal before i move.. also how do i set up a connection with my broadband settings.. or alternatively change proxy settings to use my wifi on our campus? thank you in advance for any responses!!