What is the best 3rd party checkout payment processing app?

[JuliesHC]

I have yet to find a google checkout or Paypal

checkout type of payment processing

application that includes a shipping

calculator that allows my customers to

checkout my items by weight so that the final

total include a correct USPS shipping ammount

based on weight of the package to be shipped.
Does anyone know of the best 3rd party payment

processing program to use or does anyone know

of a good widget to use?

Thank you,
Jim

[bugman]

I just signed up with Paypal standdard after looking at many alternatives.

One I found that seemed very cost effective and when you call you actually get a person to talk with was www.kingcart.com.  They don't seem real pollished in their presentation but their reviews are great and their reference sites look ok.

Despite that, I came to PayPal even with all of the complaining they seem to be the easiest to integrate with and their costs, by what I've seen are attractive. 

Good luck