Does anyone know of a cost-effective solution that a web artist/ designer could offer his clients to allow site visitors to choose which language he prefers to view the site in? The results should, of course, always have the same graphics and layout no matter which language is chosen.

Do the translated pages have to be resident on the server or is there any software or solution that allows translation "on demand". The "on-demand" translation option is really what is preferred. My budget would not be too high as I am a small, new venture and my clients are mostly small businesses or small inns/hotels who request this capability. I would like incorporate the cost into my own web design packages. I found some sites such as the altavista translator but no off -the-shelf independent packages.