In the name of Allah the Most Beneficent Most Merciful,
Giving a Cassette or Cd to someone instead of verbally giving them Da'wah by Sheikh Ibn Baaz -may Allah have mercy upon him- [Reference below]
Questioner says: I like calling to Allah and I am very interested in doing so, however I don't have a good method (in giving da'wah). So will it suffice if I just choose a cassette (or cd) from one of the Scholars or Callers to Allah and give it as a gift to one of my family members or a muslim in general?
Answer: Na'am, if the cassette (or cd) is from a Scholar known for having sound 'aqeedah and an abundance of knowledge, if you give it as a gift to one of your brothers (or family members etc.) then you have done good and you will have a similar reward due to the statement of the Prophet -sallahu 'alayhi wasallam-: Whoever directs someone to a good will have the reward like the doer of that action.[Muslim 1893]
In relation to you, then there isn't anything wrong with you relaying what you know of from the truth in a good manner. Like encouraging the people with praying in congregation, paying the zakat, warning them from backbiting and tale-carrying, disobedience towards the parents, severing the ties of the womb and all that Allah has forbidden from the other obscenities. Because these matters and their likes are well-known amongst the muslims by way of the Scholars and other than them.
Reference: Majmoo' Fataawa wa Maqaalaat Mutanawwi'ah [Juz 27 pg.141,142] of the Great Scholar Sheikh 'Abdul 'Azeez bin Baaz -may Allah have mercy upon him-