Alphabets

According to the National Language Authority [of Pakistan], Urdu has 57 letters of which 39 are basic letters while 17 are digraphs to represent Aspirated consonant made by attaching basic consonant letters with a variant of He [ھ] called Do Chasham He. Tāʼ marbūṭah [ۃ] is also sometimes considered a letter though it is rarely used except for in certain loan words from Arabic. [Wikipedia]

ا	آ	ب	بھ	پ	پھ	ت	تھ	ٹ	ٹھ	ث	ج
جھ	چ	چھ	ح	خ	د	دھ	ڈ	ڈھ	ذ	ر	رھ
ڑ	ڑھ	ز	ژ	س	ش	ص	ض	ط	ظ	ع	غ
ف	ق	ک	کھ	گ	گھ	ل	لھ	م	مھ	ن	نھ
ں	و	وھ	ہ	ئ	ی	یھ	ے

[Reference: Corpus Based Urdu Lexicon Development]

Historically there has been debates and subsequent difference of opinion on the actual number of Urdu Alphabets. A very informative article by revered Dr. Rauf Parekh sums it up nicely.

Vowels:

Romanization	Pronunciation	Initial Form	Middle Form	Final Form	Isolated Form
a	/ə/	اَندر	سَر		اَ
ā	/aː/	آم	باغ	وفا	آ
i	/ɪ/	اِدھر	دِن		اِ
ī	/iː/	اِینٹ	تِیسرا	گھڑی	اِی
u	/ʊ/	اُلفت	سُلطان		اُ
ū	/uː/	اُوپر	دُور	قابُو	اُو
e	/eː/	ایک	میرا	لڑکے	اے
ai	/ɛː/	اَیسا	کَیسا	ہَے	اَے
o	/oː/	اوس	دوست	کو	او
au	/ɔː/	اَور	مَوسم	نَو	اَو

[Reference: Wikipedia]