Is it possible to create Software on a subscription

Is it possible to create Software on a subscription model when and if the person stops the subscription the vendor (me) can stop their use of the software?... we would have given them the sw once they signed up and it is loaded on their PC and runs with a host service like host gator...is this possible? an unlimited trial version for example, would that work? any ideas?
thnx
mike

Possible yes, but keep in mind nothing is uncrackable.
I just rockstar games payed in excess of 200K to have their protection implemented on GTA 4, and it was cracked within 1 week.

But to answer possible ? absolutely.

good feedback...i cant stop the hackers from trying just trying to get the average guy to honor his subscription or force him to crack the sw for his own use...
what is needed to be done? add an isp checker? a bug?
thnx

Easy done really,
Have the program call home with the subscription type and computer id etc,
then check that against a database to make sure everything is kosher.
Else, block access to everything / certain things.
Just make sure you encrypt what you are sending, else someone will release a patch to fake communications
Also, have heaps of 'checkpoints' in your code, like verifying certain parts of the executable haven't been mucked with
If you want to deter the average reverser, make part of the code morphic, ie it re-encrypts it self every run.

What jarhead suggested...

Keys/Codes all of that crap will keep the average joe out, but any skilled cracker will probably break it in less then a day(if even that long).

The best solution would be similar to what jarhead said at the end, make part of the code encrypted, or actually make your program rely on data that cant be retrieved without communicating with the server, this in my opinion is the best method and its why so many corporations are turning towards streaming apps on http.

So do a hybrid.