Talk Talk a UK telecoms company are currently sponsoring X-Factor (the UK version of Pop Idol). They are using to great effect (in my opinion) Neon Rainbow by The Box Tops. The song gets stuck in your head whether you're watching the show or writing your blog while your wife watches it. Does it make you buy their services? No but it's there for brand building, the advertising salesman's biggest ever con.
The Box Tops were a group from the sixties who mainly did covers but they did have a couple of gems up their sleeves including The Letter and this Neon Rainbow. It's interesting by the way that the two songs mentioned above are soul songs, is there a reason they work so well in adverts?