According to Nintendo representatives, Donkey Konga will be released on September 27th for $49.99 with the conga drums packed in. The drums alone will be later released at a price of $24.99, though Nintendo is supposedly trying to lower the price to $19.99.
As for Donkey Kong Jungle Beat, whether the conga drums will be packed in or not has yet to be determined. According to Nintendo, the success of Donkey Konga is the deciding factor of their inclusion in Jungle Beat. If Donkey Konga sells past a certain margin, Nintendo won't include the drums in Jungle Beat due to them already being fairily wide spread. If Donkey Konga doesn't sell as well as they hope, though, then they'll pack the drums in with Jungle Beat so more people can get them.