Simply go to Synaptic and search for:
myspell
Now check among the results for the ones that end on "en' or "es"(for spanish).
Check all that apply, reading carefully their descriptions and making sure that they're the languages you'll need. Then hit "Apply", install all the needed dependencies that Synaptic is gonna ask for by hitting "OK" on the pop-up window, and wait for it to install. Once done fire up your Firefox and/or OpenOffice.org! You know get the red lines below the wrong words and you'll also get the spelling suggestions!
Hope this helps someone!
Oh, and tomorrow is the great day!!!! Tomorrow October 30, 2008 Ubuntu Intrepid Ibex 8.10 goes officially live!!! I'll be making a special post for tomorrow (hopefully)!
Read full post here!