Hi,

that site seems to be trying to sell ThaiMaster. If you have Xl or better, simply download the type fonts (either from the site Synthia mentions or google it - there's quite a few out there). Secondly, add Thai Keyboard to your language bar as follows (sorry if I'm preaching to the converted)...
Click Start Button, open control panel and open Regional and Language Options. Go to the second tab 'Languages' and checl the middle box at the bottom (it mentions Thai). Then click Details button at the top. Click Add. From the dropdown at te top, select Thai Kadmanee... and OK it.
Then click Language Bar Check the first box at least (I have all checked but the second one - transparancy) to show the language bar on the desktop. Click OK.
Then Click Key Settings and set up a fast key swap for English and Thai so you can switch quickly.

You may have to reboot if Windows hasn't got the complex script option installed (you also need the XP Disk).

Now when you are in an app that allows complex text (most of them) - such as Notepad for example, click the language bar and change to thai (or use swap keys) and start typing. To change back to Englsh - mid sentance - just switch back using the keys or language bar.

On keyboards, I find it easiest to simply have two keyboards and swap them as I want. If I'm on my laptop, I wwwuse onscreen keyboard (Start-Accessories-Accesabilities).

All this will cost you zip (with the exception of the physical keyboard or forever-falling off-stickers)