Instabill . :)
I used them before and have been quite satisfied with them.
They are free to start up with.
By the way, take a look at this list.
<b>»</b> <a href="http://www.authorize.net" target="new">Authorize Net</a><br>
<b>»</b> <a href="http://www.ccslide.com" target="new">CC Slide</a><br>
<b>»</b> <a href="http://www.charge.com" target="new">Charge dot Com</a><br>
<b>»</b> <a href="http://www.ccslide.com" target="new">CC Slide</a><br>
<b>»</b> <a href="http://www.combill.com" target="new">ComBill</a><br>
<b>»</b> <a href="http://www.customcart.com" target="new">CustomCart</a><br>
<b>»</b> <a href="http://www.cybank.net" target="new">Cybank</a><br>
<b>»</b> <a href="http://www.cybercash.com" target="new">CyberCash</a><br>
<b>»</b> <a href="http://www.cybermoola.com" target="new">CyberMoola</a><br>
<b>»</b> <a href="http://www.echarge.com" target="new">eCharge</a><br>
<b>»</b> <a href="http://www.ecount.com" target="new">eCount</a><br>
<b>»</b> <a href="http://www.ecx.com" target="new">E-commerce Exchange</a><br>
<b>»</b> <a href="http://www.escrow.com" target="new">Escrow</a><br>
<b>»</b> <a href="http://www.ezcmoney.com" target="new">EZCMoney</a><br>
<b>»</b> <a href="http://www.iauthorizer.com" target="new">iAuthorizer</a><br>
<b>»</b> <a href="http://www.ibill.com" target="new">iBill</a><br>
<b>»</b> <a href="http://www.iescrow.com" target="new">iEscrow</a><br>
<b>»</b> <a href="http://www.instabill.com" target="new">Instabill</a><br>
<b>»</b> <a href="http://www.ipin.com" target="new">iPin</a><br>
<b>»</b> <a href="http://www.aboutnewco.com/solutions/isell/" target="new">i.Sell</a><br>
<b>»</b> <a href="http://www.itransact.com" target="new">iTransact</a><br>
<b>»</b> <a href="http://www.paypal.com" target="new">PayPal</a><br>
<b>»</b> <a href="http://www.paytime.com" target="new">PayTime</a><br>
<b>»</b> <a href="http://www.privacybank.com" target="new">PrivacyBank</a><br>
<b>»</b> <a href="http://www.procart.com" target="new">ProCart</a><br>
<b>»</b> <a href="http://www.propay.com" target="new">ProPay</a><br>
<b>»</b> <a href="http://www.qpass.com" target="new">QPass</a><br>
<b>»</b> <a href="http://www.quickbuy.com" target="new">QuickBuy</a><br>
<b>»</b> <a href="http://www.revecom.com" target="new">Revecom</a><br>
<b>»</b> <a href="http://www.rocketcash.com" target="new">RocketCash</a><br>
<b>»</b> <a href="http://www.skipjack.com" target="new">Skipjack</a><br>
<b>»</b> <a href="http://www.tradesafe.com" target="new">TradeSafe</a><br>
<b>»</b> <a href="http://www.verisign.com/payment/" target="new">Verisign</a><br>
<b>»</b> <a href="http://www.visabuxx.com" target="new">Visa Buxx</a><br>
<b>»</b> <a href="http://www.wave.com" target="new">Wave Systems</a><br>
<b>»</b> <a href="http://www.webcharge.com" target="new">WebCharge</a><br>
<b>»</b> <a href="http://www.web-charge.com" target="new">Web-Charge</a><br>
<b>»</b> <a href="http://www.worldpay.com" target="new">WorldPay</a><br>
Sorry about the html codes, I am too busy and lazy :p to remove them.