For those of you with a sense of humor, try reading this account of a young man who was suspended for reciting his own pledge of allegiance to the Federation of Planets.
On a more serious note, I wonder why exactly schools choose to force participation in these silly patriotic enterprises. It's like when you toss Christmas parties at work: it doesn't really inspire any new fondness for your coworkers. If you had any fondness for them, you probably welcome the chance to hang out with them. If you didn't, the promise of a free dinner and booze is hardly likely to make any lasting change in your opinions.
If you'd like your children to have feelings of genuine patriotism for your country, here's an idea: work to make sure your country is actually deserving of your respect. No country which promises freedom should require loyalty pledges.
From Thoreau's CIvil Disobedience:
The mass of men serve the state thus, not as men mainly, but as machines, with their bodies. They are the standing army, and the militia, jailers, constables, posse comitatus,(5) etc. In most cases there is no free exercise whatever of the judgment or of the moral sense; but they put themselves on a level with wood and earth and stones; and wooden men can perhaps be manufactured that will serve the purpose as well. Such command no more respect than men of straw or a lump of dirt. They have the same sort of worth only as horses and dogs. Yet such as these even are commonly esteemed good citizens. Others, as most legislators, politicians, lawyers, ministers, and office-holders, serve the state chiefly with their heads; and, as they rarely make any moral distinctions, they are as likely to serve the devil, without intending it, as God. A very few, as heroes, patriots, martyrs, reformers in the great sense, and men, serve the state with their consciences also, and so necessarily resist it for the most part; and they are commonly treated as enemies by it.