The proposal--expected to be made public soon after Tax Day--would rewrite the ground rules for Internet and mail order sales by eliminating the ability of Americans to shop at Web sites like Amazon.com and Overstock.com without paying state sales taxes.

Dick Durbin of Illinois, the second most senior Senate Democrat, will introduce the bill after the Easter recess, a Democratic aide told CNET.

"Why should out-of-state companies that sell their products online have an unfair advantage over Main Street bricks-and-mortar businesses?" Durbin said in a speech in Collinsville, Ill., in February. "Out-of-state companies that aren't paying their fair share of taxes are sticking Illinois residents and businesses with the tab."