It has only been operating for a few hours now. But already a toll free telephone number is the hottest number in town.

It's the phone number to get on the state's official no-call list -- the one that will ultimately keep most telemarketers from bugging you.

State regulators and people from the private firm that set up the state's no call list proudly showed it to reporters Wednesday morning.

By mid-morning, more than 1,200 households were registered on the 'no-call' list, according to Boulder-based e-InfoData, which maintains the Web site.

"We knew it was going to be wildly popular," said Lee Sands, e-InfoData president and chief executive officer.

Lawmakers approved a law establishing the no-call list last year. Enforcement begins July 1.

By the end of this month, the first official no-call list will be ready.

Public utilities commission chairman Bruce Smith said that on July 1, most commercial telemarketers will have to start using it.

You won't have to pay a penny to be listed and you can sign up on the internet or on the phone.

The toll-free number is (888) 249-9097, or it's on the Internet at www.coloradonocall.com.

If you're on the unofficial list of some 300,000 customers -- the one the Big Horn Institute started gathering last year -- you'll be contacted and your number verified.

Remember, though, the no call list is only for residential customers.

And, when it takes effect July 1, it does not cover calls from charities, from political organizations, or businesses with whom you already have a relationship.

Colorado is one of 21 states that have enacted or are implementing laws to create no-call lists.

"It's a pain when you're trying to eat dinner or spend some time with your family," said Monique Losake of Lakewood, who planned to register her name on the list via the Internet.

Parker resident Janet Sprecht said she is still debating whether to add her telephone number to the list.

"There are programs I'm in favor that I want to continue hearing from and I want to continue to support," she said. "But if I get enough of those phone calls in one day I just might do it.

"There's so much of it, you get to the point where you don't want to answer your phone."

Telemarketers fought the passage of the legislation, saying it duplicates existing efforts by the industry and the federal government and could negatively impact thousands of jobs.

"They have redress right now and many folks don't take advantage of it," said Louis Mastra of the Direct Marketing Association. "Many just hang up the phone in frustration when it's just as easy to say put me on your do not call list, goodbye."

The association has maintained a no-call list since 1985 and it has 4.5 million registrants nationwide.

In Colorado, the industry employs 108,000 people and about $11 billion in sales was conducted over the telephone last year, Mastra said.