(FORTUNE Magazine) – Miss Piggy might snort at the thought of sharing center stage with Minnie Mouse. But she'll have to get used to it because the piggadonna, Kermit the Frog, and scads of other Muppet characters are moving to the Magic Kingdom. The Walt Disney Co. agreed to acquire Henson Associates, the privately held company founded by master Muppeteer Jim Henson that owns the Muppet menagerie. Estimated price: between $100 million and $150 million. Though the sale does not include Henson's familiar Sesame Street creations -- Big Bird and friends -- which are controlled by the nonprofit Children's Television Workshop, Wall Street analysts say that adding Henson's pig and frog to Disney's mice and ducks is a synergistic master stroke. ''Kermit's charisma and Disney's marketing ability are a powerful combination,'' says Liz Buyer, an entertainment analyst at Prudential-Bache Securities. Disney gets Henson's film and TV library and rights to merchandise the Muppet characters. Henson will produce movies, TV shows, and videos for Disney and Muppet attractions for its amusement parks. First up: a 3-D Muppet movie for the Disney-MGM Studios theme park in Florida next May. The Mickey Mouses and Bugs Bunnys of this world appear to command increasing value in a global village smitten with television. Another character, Sea World superstar Shamu, the killer whale, is now on the block along with the four Sea World theme parks and other entertainment assets, which together % could fetch some $1.5 billion for their owner, Harcourt Brace Jovanovich. But don't look for a tidal wave of sales to follow. Says Harold Vogel, an analyst at Merrill Lynch: ''The big characters are controlled by major corporations, and they don't come up for sale often.''