Telephone companies can dive into California's $5.3 billion-a-year cable TV industry under a law signed Friday by Gov. Arnold Schwarzenegger. He said the measure, backed by millions of dollars in corporate contributions, will offer consumers better service and lower prices. Rushing to beat a midnight Saturday bill-signing deadline, the Republican governor joined with Democratic legislative leaders Friday to also back programs lowering the cost of prescription drugs for poor Californians and to test thousands of volunteers for possible toxic contamination. All three bills could serve as models for other states and the nation, supporters said. AT&T Inc. and Verizon Communications...