The best way I found to translate Excel tables to LaTex is using OpenOffice (Excel2Tex add-in in Excel sucks! Or at least, so it does on my Pc using XP & Office 2007)

Once you have installed the latest OpenOffice release, follow:
The code is taken from:
You can also add a botton in the toolbar (quoting from jarom):
To add a toolbar button (or Menu item):