I don't mean to start an internet fight, however... Traffic between your site and the users browser is not being encrypted by the transport protocol (you're not using SSL/https ) which means no its not secure enough for me to stick my credit card info in a form and send it in plain text to your server.... period.
I'm a web developer and using SSL is the minium standard for any sensitive data like credit card, banking, or health care info.
If you don't believe me thats fine download 'httpfox' for fire fox and run a trace. When you submit the credit card in step 4 of checkout the browser posts this data in plain text (over http ) to this url:
http://chuggerpumps.com/checkout_db.php?step=4
POSTED DATA:
name=chris+kwjsdflkjlsdf&cctype=Master+card&ccno=234234234234&dig=323&exp_month=January-01&exp_year=2012&s.x=16&s.y=7
ccno=234234234234 is the credit card i inputed... Trust me, not good. That post needs to go over https.