I am developing a system where:
- Users can go to a website, sign up for classes, and pay for classes
- Or they can come to the store and sign up in person

I was wondering if someone could walk me through the steps from the beginning of making this system so I could have the customers' online info go to the database which will be stored on by webhosting service. The catch is that I also want to be able to enter info for the people who sign up at the store into the database. How could I make it so that all this is real time where when a person signs up on one it integrates to the other? I really have no idea where to start so any help would be appreciated, thanks!

well there are many things you need to tell us first, what language you plan on using the integrate the database with is a biggie, eg: PHP, ASP, JSP, CFM, etc...

you also need to figure out ALL the information you intend to capture and store in the db. If your working with a database it will be real time, that isn't an issue (since I doubt you will be issuing any rollback commands). This seems like a really in-depth problem, I highly recommend picking up any book on PHP & MySQL, any decent book will walk you step by step on how to do a number of similar problems, if you need a reference for a good book let me know (that's assuming your going to use PHP of course)

Also, plan on having the store access the same database as the website. That way you can keep info in real time and not mess with dumping data and importing on some schedule.

entering info in-store isn't an issue, you could just go to your own website to do it! one major component is how you plan on accepting online payments. you'll need a merchant account and an online processor for cc transactions, or maybe paypal if you don't mind the minor intrusion on your users' experience. you definitely do not want to be storing credit card info on your server, especially one you don't have complete control over, huge liability.