I believe he is an Evangelical Christian.
Pat Toomey was raised Catholic, and apparently he’s still Catholic:
http://www.adherents.com/gov/congress_108.html
http://www.archphila.org/cst_archives/040422/fifth.html
http://www.nndb.com/people/779/000040659/
http://www.ontheissues.org/PA/Pat_Toomey.htm
http://en.wikipedia.org/wiki/Pat_Toomey
And Michael Barone’s 2004 Almanac of American Politics (the last Almanac in which Toomey was listed as a member of Congress) also identifies him as a Catholic: http://www.nationaljournal.com/pubs/almanac/2004/people/pa/rep_pa15.htm