The listing, Sgt. Frog Manga #15 English has ended.
When Fuyuki wakes up to find a froglike alien in his bedroom, he's delighted—after all, he's head of his school's occult club. But poor Sergeant Keroro is now stranded without his squad in a failed invasion of Pokopen (Earth), forced to feign bonhomie as he does housework for the Hinata household to earn his keep. Keroro, called "that stupid frog" by big sis Natsumi, perfects his cleaning techniques while replotting his invasion and building Gundam models in his basement quarters. Then one by one the squad turns up—dopey and devoted Tamama, grim Geroro, techno nerd Kululu, pacifist ninja Dororo—and the team teeters comically between luxurious slackerdom and military purpose.
A dozen other nutcase characters round out the cast in plots that rival Gilbert and Sullivan for high-speed goofiness and incorporate numerous references to Japanese pop culture. In the latest volume, the platoon tries to subdue the Hinatas with laughter using a traditional New Year's game, Geroro's cat steals the sergeant's star and becomes de facto commanding officer, and Dororo's ninja gal pal tries to be "normal"—unsuccessfully.
The slapstick art suits the action, with occasional mild fan service. Tokyopop is rereleasing earlier volumes in library binding, some in omnibus editions, and the derivative 200-plus episode anime has been licensed by FUNimation. Great fun for teens up.
(from: http://www.amazon.com/Sgt-Frog-Vol-Mine-Yoshizaki/dp/1427810397)