who offers nationwide wifi access?

Answer 1

http://www.verizonwireless.com does but its pretty expensive. I would go to http://www.google.com and enter "nationwide wifi " without the quotes and you might have more options in your area.
AT&T and T-mobile has nationwide WIFI as well. Most cell phone companies have this feature.

So does Intel and IBM.

Check their website:
http://www.intel.com
http://www.ibm.com