Sales taxes for Internet purchases--currently a crazy quilt of rates from state to state--are moving toward a uniform reality. Several states have banded together to create a data and tax collection infrastructure that likely will be in place by the end of the year.

"States are pushing hard to have a voluntary system up and running by the end of the year," said Charles Collins, vice president of government affairs at sales tax software provider Taxware Inc., in an interview Wednesday. "Then Congress will probably take at look at it this year. Much of this is about education."

With different states and different on-line retailers taking different positions on sales taxes, the issue is complex. But with state and local governments complaining they are losing more than $15 billion annually in lost taxes from Internet sales, the issue is gaining importance.

Working under the umbrella of the Streamlined Sales Tax Project (SSTP), some 40 states have issued Requests for Proposals to software providers to supply a sales tax infrastructure. One RFP seeks bids for sales tax software for retailers while a second RFP would establish a registration system for all Internet retailers. The bids are expected to be announced next month.

Collins, a former co-chair of the Streamlined Sales Tax Project, said several states have voluntarily signed on to instituting a sales tax collection system. Once the voluntary approach is in place--presumably by the end of the year--Congress is likely to make a serious effort to pass federal legislation that would oversee the collection of sales taxes. Collins noted that there are already bills in Congress that use the voluntary measures adopted by the states. Congress, he added, would likely add a few points of its own to the legislation.

Many online retailers already tax online sales voluntarily, while others are expected to phase in sales taxes gradually from state to state.

States that have signed on to the voluntary approach include Arkansas, Indiana, Iowa, Kansas, Michigan, Minnesota, Nebraska, North Carolina, North Dakota, Ohio, Oklahoma, Kentucky, South Dakota, Tennessee, West Virginia, Wyoming, and Vermont.

The three largest U.S. states--California, New York, and Texas--have not yet joined the group.

Collins said the new infrastructure will enable Taxware and other firms currently providing tax software to improve the software they provide to retailers.

The RFPs are confidential, and Collins declined to name any bidders or teams of bidders. Taxware is expected to bid on the registration system as is its competitor, Vertex. Other firms mentioned as possible bidders include Accenture, EDS, IBM, KPMG, and Tax Matrix Technologies.