Target is sending out emails today encouraging customers to buy an iPhone 4 for their mothers for Mothers Day (this Sunday, in case you didn't know). They're calling it the gift "she'll use every day."
If you're on the frugal side, they'll even let you trade in your own iPhone 3GS or 3G to knock off $150.
Note that this is at "select" Target stores. It doesn't appear that they even sell the iPhone 4 on their site (though they do provide a variety of accessories). It's unclear whether the new White model is available as an option.
Back in November, Target announced it would carry the iPhone in 846 stores - those that include Target Mobile Centers.
If you do buy your mom an iPhone for Mothers Day, you might also want to make sure she's aware of the whole location tracking thing that's been in the news that last couple weeks. It couldn't hurt.