If a company does not open a .com, how long before its legally up for grabs? -

It does depend on your intent. If you are doing this to sell the name to the company at higher than market price, or put up a web page that is derogatory to the company to force their hand, then you may be sued for cybersquatting.

It s becoming more and more popular for others to register domain names of new businesses (cybersquatting as stated below). All domain names are up for grabs at any time. So if you have a business name in mind, you should register your domain name right away, even if you don t plan on putting up a website any time soon. You can get a domain name for less than $10. It s well worth it.

You can buy any available .com domain at any time you want.