hmm.. I don't know about shuttles but it's really easy catching a cab from the airport. There is normally a long queue of taxis waiting for passengers. My 62yr old dad managed to take the cab and ride to town himself with zero trouble. It costs roughly 100RMB from BJ's temrinal 3 to central Beijing. That's about SG$21.

Thanks.

Some travel agencies may be running this service but I think you need to book a tour as well.

Plenty, though I have no specific recommendations apart from my own contact -- don't want to post that here otherwise it looks like an ad.

If you have up to 4 people (and not tons of luggage if 4 people), it could be easier just taking a taxi from the official airport queue though.