I'm setting up a webpage which will require visa and mastercard
transactions.  I'm looking for the best net banking system available.

I have no idea what additional fees vendors charge per transaction.  How much?

Also, if a customer pays $3.00 for an item, I'd like it to be split up
into separate accounts.  Customer pays with credit card and money hits
two or three accounts in designated percentages.

One of the simplest solutions is to setup a "shop" through a company
like Yahoo! Shopping.  They charge a monthly fee of anywhere from $40
to $300 and charge transaction fees of anywhere from 0.75% to 1.5%.

More info on that here

http://smallbusiness.yahoo.com/merchant/index2.php?rn=3180196

The nice thing here is that you get a storefront, you don't really
have to worry about creating a web page, because Yahoo! does it for
you, and it's generic enough to make life easy for you.

Depending on how much you plan to charge, you can also go with a
pleathora of compalines which can be found by typing "online credit
card processing" in your google search field.

One such company is Paynet Systems, with NO annual/monthly fees, and
they charge a transaction fee of $0.25 + 2.30% for online credit card
processing.  Retail transactions (where the card is swiped) are
somewhat cheaper.  These guys do charge a $10/month "statement fee",
which is the cost of preparing a statement for you...

http://www.paynetsystems.com/html/feelist.html

I have used Verisign's PayFlow for a few sites and was very happy with it.

http://www.verisign.com/products/payflow/link/index.html

Most credit card processing companies require a monthly fee for usage.
 However, PayPal offers a service that charges instead a small
percentage per transaction.  Depending on how many transactions you
make in a month, this might be a better solution.

With PayPal, there are no setup charges, gateway fees, cancellation
fees, or monthly charges. You can apply for the low merchant rate of
2.2% + $.30 per transaction.

What I recommend for someone just starting is to setup initially with
PayPal and see how your business does, then if it takes off, switch to
a company that is only flat-fee.

There are many many companies out there and this is something you'll
want to look at for your self because of the different benefits that
may be best for you and your business.

Doing a google on "Credit card processing" will bring up many options as well.

Good luck!

Thre is an excellent site and overview of E-Commerce web site options
available. The information has been compiled by a website designer as
information for her clients, but is often referred to by other
designers because of the information it contains.

It breaks down the differences in having your own merchant account or
using a third party process for credit card purchases.

With your own internet merchant account there can be potential fees
including "application fees, set-up fees, yearly memberships, monthly
statement charges, monthly minimums, gateway access fees, statement
fees, fixed transaction fees, variable transaction discount rates
(processing fee for each transaction), and cancellation penalties ...
plus undisclosed fees.

A third party processor is often the best way to start, and there are
examples of two or three most often used.

This site and the links help you make an informed decision of what may
be best for you.

Here's a link to the site and information,
   - http://www.take-payments-online.com/

Hope this helps,

Serenata
Google Answers Researcher