Very good news for us, Khmer, that we have now the fonts that work with Adobe CS3.
It’s easy to configure as in fact, we just install new fonts from Khmer OS (I’m not sure yet where is the source of this font), but you can download here: Khmer Unicode Supported CS3.

There are fonts:

• Kh-Battambang
• Kh-Bokor
• Kh-Content
• Kh-Fasthand
• Kh-Freehand
• Kh-Kangrey
• Kh-Koulen
• Kh-KoulenL
• Kh-Metal-Chrieng
• Kh-Muol
• Kh-Muol-Pali
• Kh-Siemreap
• Kh-System

The right font view as:

See how to do it:

1. Install fonts: Start -> Control Panel -> Fonts -> Install New Fonts -> Select Kh fonts to install

2. On Adobe Photoshop CS3, select a Kh font (Ex: Kh System)
Here Example:

Note: any font name in group of Kh font will be Ok with CS3, these fonts also can use well with embedded for website without needed usp10.dll, I’ll test it first.