Christmas is still months away, but online shopping portals are already sprucing up for the holidays with broader offerings. In the past, Yahoo Shopping (at shopping.yahoo.com) let you search only for products sold by its paid advertiser and merchant network. Now the site searches the entire Web and presents results from some 17,000 vendors. To help you pick a purchase, there are handy links to magazine reviews and experts. The new Shopping.com (formerly called DealTime) integrates more than 1 million consumer reviews from the popular Epinions website into its comparison-shopping site. One word of advice: on both Yahoo Shopping and Shopping.com, paid advertisers get preferential placement even if they don't offer the lowest prices, so be sure to scroll through all the results to find the best deals.