Singer Janet Jackson will share New Year’s Eve with MTV viewers during a live broadcast from her sold-out Madison Square Garden show, culminating with MTV personalities counting down the final seconds of ’93 in Times Square.“Janet’s Live New Year’s Jam,” a 30-minute broadcast, will incorporate the singer’s tour stop with the countdown. Jackson kicks off her highly anticipated tour today in Cincinnati. The music channel’s New Year’s Eve festivities will include a 90-minute concert from Seattle before the Jackson segment. Grunge rockers Pearl Jam and Nirvana will join alternative faves the Breeders and rappers Cypress Hill in “Live and Loud,” a concert taped earlier in the Northwest city and airing at 10 p.m. The program will be hosted by Anthony Kiedis and Flea of the Red Hot Chili Peppers. MTV’s “Top 100 Video Countdown” will air throughout the day and precede the special programming. “Live” and “Janet” will be rebroadcast after midnight.