Just saw the Sprint AAdvantage offer just increased to 25K miles right off the bat and 5K for each year. Used to be 20K off the bat and 5K for the year.
If you are thinking about switching to Sprint, you might as well register your AAdvantage #, as this deal stacks with every current Sprint deal out there (phone and plan deals), with the exception of corporate discounts.
Also, as usual, existing Sprint customers can register their AAdvantage #s and start earning 5,000 miles per year. Easy way to keep your AAdvantage miles active as it posts as 417 miles per month.