I am looking for a study that shows the effects (hopefully postive) on
having a major leauge baseball stadium/park in the city and more
specifically, the influence on the neighborhood where the park is
located.  I am looking for stats and info about housing developments,
retail outlets, and various other things around baseball stadiums in
America.

Unfortunately, in th einterest of accuracy, something positive in
terms of economic impact may be hard to find:

"The primary conclusions are: first, sports teams and facilities are
not a source of local economic growth and employment; second, the
magnitude of the net subsidy exceeds the financial benefit of a new
stadium to a team; and, third, the most plausible reasons that cities
are willing to subsidize sports teams are the intense popularity of
sports among a substantial proportion of voters and businesses and the
leverage that teams enjoy from the monopoly position of professional
sports leagues."
 
"Sports, Jobs, and Taxes: The Economic Impact of Sports Teams and Stadiums"
by Roger G. Noll, Andrew Zimbalist 
http://www.amazon.com/exec/obidos/ASIN/0815761112/ref=ase_ballparks/102-2719562-5760152

It seems then (and this is just my guess since its basically the only
thing left) that stadiums and ball parks are not erected for the
purposes of economic impact alone so much as they provide a measure of
civic pride, recreational convenience and pleasure to voters.

Good luck;
tutuzdad-ga