There are many ways of creating a Jingle. Firstly, by using a royalty free sound track that already exists. This means by law the person is clear from breaching copyright. There are to different forms of copyright.
Intellegent – This is where the artist has legal ownership to there work. Both to their Compositions and lyrics.
Mechanical – This is where the record label have some of the copyright ownerships, when artists record at there studios.
The other way of creating a Jingle is to use ProTools and use instruments to create a beat.
I personally prefer the first way as it is easier and it matches then tone of the Podcast i am trying to capture. This also is the preferred way if time is running out.