If you’re in the US and you use Verizon or AT&T for your cell phone carrier, you may be wondering if you’re eligible for an upgrade and how much it will cost to get a shiny new iPhone 4. Apple can help you out – they’ve posted a Web page to help you check.

Right now the page checks your account status on AT&T or Verizon, depending on your carrier, but Apple notes that Sprint is coming soon.

Interestingly, Apple’s beaten AT&T to the punch – we tried to check on AT&T’s Web site earlier today but couldn’t get any information about the iPhone 4S.