Guide to editing /etc/hosts
/etc/hosts doesn't allow wildcards (see here: https://serverfault.com/questions/118378/in-my-etc-hosts-file-on-linux-osx-how-do-i-do-a-wildcard-subdomain).

Two more links about /etc/hosts:


HOWTO Configure your hosts file: http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:Ch03:_Linux_Networking#Configuring_Your_.2Fetc.2Fhosts_File
Large example file with nice intro header: http://someonewhocares.org/hosts/
Small Android app that allows you to add an entry to the hosts file (requires root): https://market.android.com/details?id=com.pof.Add2Hosts