Nicely written letter. I like the way you chose to keep your sentences short. I am also impressed that you correctly used the words which and that. These are often used incorrectly even by native English speakers. I have some corrections that you might find helpful.

Letter to a Programme (<em>Headings are normally capitalised in a particular way in English</em>)

Dear Sir or Madame,

I'm writing in connection with the comic programme "Politicians in Wonderland" which I saw this morning. 
I must say that I found the journalist very funny and polite.

First of all, he didn't start an argument with the politician that was rude with to him. I totally agree with his opinion about the education with other people. <em>(Grammatically correct but I don't understand what you mean by "the education with other people".)</em>

Then, he did made <em>(or cracked)</em> many jokes. He was very funny.

Finally, he helped a citizen with a problem. He's been very helpful. <em>(This last sentence probably doesn't convey the precise meaning that you intended. It is the repeated use of help that is confusing.)</em>

Your faithfully,

 
Joanne Smith

Letter to a programme

Dear Sir or Madame,

I'm writing in connection with the comic programme "Politicians in Wonderland" which I saw this morning.
I must say that I found the journalist to be very funny and polite.

First of all, he didn't start an argument with the politician who was rude to him. I totally agree with his opinion about the education with other of (other) people.

Then, he did many made a lot of jokes. He was very funny.

Finally, he helped a citizen with a problem. He's been very helpful.

Your faithfully
Joanne Smith