Pet carriers

I have been looking for a good pet carrier for my cav, as when you are travelling on trains, and buses etc I find sometimes it would be useful. I would like something very practical, which maybe looks like a sports bag, also something which is easy for my dog to get out of ( when i want him to). I have seen these things called pet slings, but am not sure whether that would be suitable for a cav.
Has anyone used any of these carriers? Do you know anything suitable for a cav?

http://www.petlondon.com/

if you go to the carrier section there is a kinda backpack that would probably do you fine.
if you live in london i'm sure they have a shop that you can go to you lucky thing!!!

Remember that he is likely to get larger than some of the small dog carriers. I have a Sherpa shoulder bag that carried mine when they were small.

This is similar:

http://www.petplanet.co.uk/product.asp?dept_id=151&pf_id=4295

When he is larger you can get under-the-seat carriers by Sherpa for example.

I was lucky enough to win a Pet Stroller from www.doghealth.co.uk in a magazine giveaway.

This was very useful for Peaches when she was so poorly and couldn't walk very far, also for me as it meant I didn't have to carry her.
It takes dogs up to 25lbs, so most Cavaliers would be ok.

There is a clip inside for attaching to their harness {preferably} or collar, so they are secure.

They also now do larger ones too...just noticed