NEW YORK -- Pop singer Britney Spears plans to marry her latest boyfriend, a dancer who is awaiting the birth of the baby he fathered with another woman. ''I can confirm that yes, she is engaged,'' said Sonia Muckle, a spokeswoman for Spears' record label, Jive Records. Spears, 22, and Kevin Federline, 26, have not yet set a date, Muckle said. The two began dating a few months ago, after Spears' whirlwind wedding to childhood friend Jason Alexander in Las Vegas in January. That marriage was annulled within days. Federline appeared in the movie ''You Got Served'' and performed as...