Well, maybe not that soon. Sprint's WiMAX offering, Xohm, will be rolling out, according the the brand new Xohm website, in the Spring of 2008:
The Internet is on the verge of another revolution. Coming in Spring of 2008, Xohm promises to bring fast, secure and smart wireless access to cities, enabling the possibility of a whole new range of high-bandwidth applications and uses. Xohm also will expand the Internet experience by partnering with the best companies in the industry to enable a new class of devices with Internet capabilities. Beyond just laptops, the vision of Xohm is to empower PMPs, video cameras, MP3s and more with Internet access.
Not much more info than that right now, not even which cities, but it's good to know that 4G goodness is just a baseball season away. For at least 100 million people, anyway.