What's with the Crazy Poll Number?

A 15 point spread in the national polls? Really? The margin of error is typical 3-4 points, but this spread suggests someone doesn't know how to run a poll, or at least doesn't know how to run a fair poll. Is this 'Obama bounce' manufactured or have the last two weeks given American's incredibly mixed feelings?

Poll	Date	Sample	Obama (D)	McCain (R)	Spread
RCP Average	06/15 - 06/25	--	48.0	41.2	Obama +6.8
Gallup Tracking	06/23 - 06/25	2605 RV	44	44	Tie
Rasmussen Tracking	06/23 - 06/25	3000 LV	49	45	Obama +4.0
LA Times/Bloomberg	06/19 - 06/23	1115 RV	49	37	Obama +12.0
Newsweek	06/18 - 06/19	896 RV	51	36	Obama +15.0
FOX News	06/17 - 06/18	900 RV	45	41	Obama +4.0
USA Today/Gallup	06/15 - 06/19	1310 LV	50	44	Obama +6.0