Walmart has unveiled new apps for the iPad and the iPhone that allow shoppers to browse inventory at their local store, scan products and create voice-activated shopping lists.

The iPad app debuted last week and the response has been “phenomenal,” said Gibu Thomas, Walmart’s senior vice president of mobile and digital. The new version of the iPhone app includes both a bar code scanner and a QR code scanner. The new voice-activated shopping list can also help customers find coupons and provides a running tally of the bill.

Thomas said the apps were designed as self-service tools for shoppers and to help the big box retailer create more personal relationships with its customers. The iPhone app, for example, will remember items frequently added to a user’s shopping list.

“We look at this as a great opportunity to help our customers shop better with Walmart and have a much more convenient way to access our low prices,” Thomas said.

According to IBM Coremetrics, mobile sales made up nearly 10 percent of online retail sales last month, compared with just 3.4 percent a year ago. Meanwhile, about 6.5 percent of people who browsed products using an iPad made a purchase, compared to just 3.6 percent of of all mobile users.

Of course, Walmart is not the only retailer betting on apps. Internet giant and rival Amazon launched an app called WindowShop for the iPad last Christmas. Macy’s created the Believe-o-Magic for the iPad that allows users to pose for photos with animated characters and e-mail them as holiday cards.

Sears, on the other hand, is putting the technology in employees’ hands, equipping many of them with iPads and iPod Touches. Salespeople can use the devices to showcase products, search for merchandise and order products online for customers.

“Leveraging wireless access and mobile technology and putting new tools into the hands of our associates and customers is another step toward becoming a truly integrated retailer,” said Deidra Merriwether, senior vice president at Sears.