Making an invoicing database in Access, need assistance?

I am trying to build a copy of this following site online

http://www.fakturor.nu/default.asp

Excuses for the Swedish language. If you want to help out, feel free to login on that page with demo/demo as username/password to see what it is. It is a database app for keeping track of and send invoices to your customers. I already started creating the different tables inside Access2007, but I was wondering whether some people here on fluther wants to help me out when I run into problems. Maybe I should start building already in MySQL or something instead. Any take on this would be highly appreciated. Feel free to contact me privately, I would love some smart minds to brainstorm together with. Maybe emailing would be a good idea, or maybe even IM. A cool littel team effort would be fun!