Pay-as-you-go cell phone provider kajeet has landed its first kids content partner, and it’s a whopper! Nickelodeon has agreed to license its portfolio of properties to the Bethesda, Maryland-based company, which will turn them into a range of downloadable ringtones, wallpapers, and games featuring the likes of SpongeBob SquarePants, The Fairly OddParents and Rugrats.

All of Nick’s channels and platforms will hype the branded service, which launches on April 13 in tandem with the SpongeBob SquarePants ‘Friend or Foe’ stunt. In conjunction with this special episode, kajeet will exclusively sponsor the Trash Bash game of the week on www.Nick.com and www.dudes.kajeet.com.

kajeet’s full-function phones include voice, text, picture and instant messenging capabilities and started rolling out at mass retail last month. They are pegged to be available in more than 500 Best Buy stores by May 1.