how would i go about registering a client's domain name for them? would i charge it under my credit card using their information? do i direct them to register it themselves? i'm not sure how this part works. :(

You might want to look into reseller programs offered by the various registrars if you register enough. Some programs are easy, some more difficult to implement, some cost money upfront, some don't.

hmm... then which ones would you recommend that i use or at least look into? what's the best way to handle the domain registration process for your clients?

Easy:
http://www.itsyourdomain.com
http://www.domainbank.com
(probably a bunch more, check ICANN list (http://www.icann.org/registrars/accredited-list.html))

Harder:
http://www.OpenSRS.com
(probably a bunch more, check ICANN list (http://www.icann.org/registrars/accredited-list.html))

Really, there aren't all that many accredited registrars, and a quick look though 10 of them will give you an idea of some of the reseller opps. available to you. The above two are easy since you don't even have to have a SSL cedrt. or processing capabilities (they process your customer's card on their site).

IMHO, this is better than them ordering it from you, paying you, then you ordering the domain, paying them, etc. Worth checking into at least.

There are others but my experience with them has not been good and these are three places which seem to at least have their acts together for the most part.

I have a couple dozen domains both in house and clients. The current registrar I use is http://www.AllDomains.com The names are $12/year and I charge my client the going rate $35. Take the ~20 client names X $23 markup = $460/yr income. I can also waive the domain fee for annual hosting payment, I don't mind losing $12 bucks for a years worth of hosting fees.

If you don't have many names to register I would have the client register them themselves.

-Bubba

Registering the domain name is a good service to offer clients. You can't count on a non-technical customer to do it right or timely.

Check out http://www.dotregistrar.com - They also have API scripts

I use registrars.com. I am able to use their email templates and I just add the charge on their bill. They give you a discount and you can make some money as well. They can also charge the card for you but I do not think you can use it with your registration system