Today I installed VMware Workstation 5.5.3 in Ubuntu. This couldn't be easier. 

Just download the .tar.gz package and unzip it with:

tar zxvf VMware-workstation 5.5.3-34685.tar.gz

go to the vmware-distrib folder:

cd vmware-distrib

and start the installer:

sudo ./vmware-install.pl

Just <enter> through the whole setup, create a shortcut on the desktop

Command: /usr/bin/vmware

Icon: /usr/share/pixmaps/wmare-workstation.png

Start it, go to 'Help, Enter Serial Number...' and enter the serial number.

You're good to go!