Thinking about entering the network news business? NBC's Maria Shriver has some advice for you.

"Go to a local station," Shriver counsels. "Work as a producer. Learn how to write. Learn how to log your own tapes. Learn how to do the sound. Learn what it takes to shoot, to set up your own things so, if you're in the field and you're by yourself, you can take care of yourself."Shriver should know. Famous last name and links to the Kennedy clan notwithstanding, the broadcast newswoman who hosts tonight's NBC News special, Women Behind Bars (9 p.m., Ch. 2), worked her way up through the ranks to her current position of national prominence. In addition to doing the occasional news special, Shriver is co-anchor of NBC's "Sunday Today" and host of the network's youth-oriented "Main Street" news magazine.

But it wasn't always thus. She started her career in broadcast journalism in 1977 as a newswriter/producer for a Philadelphia television station. A year later she moved on to Baltimore as a writer/producer for a local evening magazine show. Later stops included two years as a correspondent for "PM Magazine" before she hooked on with CBS as a Los Angeles-based reporter and, later, as co-host for the "CBS Morning News." When that program folded in favor of the late, unlamented "Morning Program," Shriver moved to NBC, where she has been since late 1986.

It was a long way to the top, she allows, but she's grateful for the training she received along the way. "Shows like `PM Magazine' teach you how to take care of yourself," Shriver said during a recent interview in Los Angeles. "That's important, especially when you get to the network level, because no one has time to teach you at that point. They just say, `Here's your job move it.' And you better know how to do it."

Which is not to say her local news experience prepared her for everything she was going to have to do at the network. "I remember the first time I did the `CBS Morning News'," she says now, laughing. "It was like `Broadcast News.' I was throwing up, sweating everything."

She's calmer now, but that doesn't help make tonight's "Women Behind Bars" significantly better than the shallow psuedo-documentary that it is. The report, which focuses on a women's prison in Illinois, was intended as an examination of the peculiar problems encountered by female prisoners. Shriver pays particular attention to the women who are mothers, and tries to elicit sympathy by talking about how difficult it is to be a decent mother when you only get to spend an hour or two with your child each day.

But she fights a losing battle here. I mean, how many tears can you squeeze out for women who are convicted felons? If the special's focus had been on the plight of children who receive insufficient care because mama's in the pokey, that would've been another thing. But if you're trying to make me feel sorry for murderers, arsonists and drug dealers whose maternal desires are going unfulfilled, I'm sorry. There are other things to worry about.

Like how did a jet-setting journalist like Shriver survive living in a Holiday Inn while spending several weeks in prison? "It was interesting," she said. "The women would often ask me about television, and they all asked me about my husband (Arnold Schwarzenegger). But it was very different than one imagines. It's not a violent place."

I assume she was talking about the prison, not the Holiday Inn.