Judging by the dearth of Vietnamese restaurants in these parts, it seems that South Florida hasn't been the first choice for emigrants from that Southeast Asian nation. At the very least, that's a culinary pity. Maybe it's the French influence, but Viet cuisine is a refreshing, light affair compared to, say, its Thai cousin, which usually comes slathered with rich sauces and big hunks o' meat. Take, for instance, Pho Nam's house specialty, the Vietnamese pancake: a thin, crispy crepe stuffed with onion, yellow beans, bean sprouts, and finely minced bits of shrimp and pork. At $7.50, it's about the most expensive thing on a menu of meals that average about $6. The spicy beef salad, a $7 specialty that won't leave you feeling bogged down after dinner, is made of thinly sliced beef, tomato, cucumber, basil, and ground peanuts over lettuce. You won't find fancy décor at Pho Nam, which lies just south of Commercial Boulevard, but you will see a steady stream of Vietnamese customers.