Yes, I'm sure you can now (since the Jan TOS update). Make sure your AdSense ads and Feedburner ads look different. I don't know much about Feedburner ads, but avoid anything that isn't family friendly in case it upsets AdSense.
The Feedburner ad is a 300x250 image about "health care coverage". 300 x 250 & 336 x 280 AdSense formats are not going to be used on the same page. So it should be OK, right?
zexy - have you had any issues with Feedburner ads and Adsense? i was just approved for feedburner and have good things about the payouts so I want to take advantage, but I am hoping someone else has run these two programs together on a site. Any info??