Though she lost out to Lady Gaga in MTV News' summer jam 2010 poll, Katy Perry is still off to a pretty good start of the season. With the help of Snoop Dogg, the singer has notched a #1 on the iTunes singles chart for the week ending Monday with her song-of-the-summer contender, "California Gurls."

The top of the list, frankly, looks like a who's who of our summer-jam nominees, with B.o.B's "Airplanes" coming in at #2, followed by Usher's "OMG," Ke$ha's "Your Love Is My Drug," Eminem's "Not Afraid" and the actual hottest summer jam, Lady Gaga's "Alejandro," as voted on by MTV.com readers.

The rest of the iTunes single chart is rounded out by La Roux's "Bulletproof," the "Glee" cast cover of Gaga's "Poker Face," Travie McCoy's "Billionaire" and Taio Cruz's "Break Your Heart."

Though iTunes does not release sales figures, the picture at the top of the site's albums chart should be familiar to anyone who saw last week's Billboard 200 chart, since it's topped by the third volume of jazz-hands-worthy covers from the "Glee" crew, Glee: The Music, Vol. 3 Showstoppers.

Just behind are reunited glam-rock survivors Stone Temple Pilots, whose self-titled comeback album will likely top next week's Billboard tally. Gaga hangs tough at #3 with The Fame; followed by the Black Keys' Brothers; the "Sex and the City 2" soundtrack; B.o.B's debut, B.o.B. Presents: The Adventures of Bobby Ray and yet another "Glee" compilation, Glee: The Music, Journey to Regionals.

The list is rounded out by Distant Relatives, the full-album collaboration between rapper Nas and reggae scion Damian "Jr. Gong" Marley, LCD Soundsystem's This Is Happening and Lady Antebellum's Need You Now.