Ich möchte...
The verb mögen ("to like") is unique amongst modal verbs in that it is the conditional form, and not the present tense, which is used with a following infinitive. We will deal with the present tense of the verb mögen and how it is used in the next chapter.
It translates as a more polite (and more restrained) way of saying "I want to" than "ich will". Thus in the final example below, it would appear rude to say: "Wollen Sie später noch mal anrufen?".
Ich will eine Nachricht hinterlassen.
(I want to leave a message.)
Ich möchte eine Nachricht hinterlassen.
(I would like to leave a message.)
Möchten Sie später noch mal anrufen?
(Would you like to ring back later?)