In modern English, the auxiliary verb for forming the present perfect is always to have.
A typical present perfect clause thus consists of the subject, the auxiliary have/has,
and the past participle (third form) of the main verb. Examples:

• I have eaten some food.


• You have gone to school.


• He has already arrived in Catalonia.


• He has had child after child... ( The Mask of Anarchy , Percy Shelley)


• Lovely tales that we have heard or read... ( Endymion (poem) , John Keats)

Early Modern English used both to have and to be as perfect auxiliaries.
Examples of the second can be found in older texts:

• Madam, the Lady Valeria is come to visit you. (The Tragedy of Coriolanus , Shakespeare)


• Vext the dim sea: I am become a name... ( Ulysses , Tennyson)


• Pillars are fallen at thy feet... (Marius amid the Ruins of Carthage, Lydia Maria Child)


• I am come in sorrow. (Lord Jim, Conrad)

http://en.wikipedia.org/wiki/Present_perfect

In modern English, the auxiliary verb for forming the present perfect is always to have.
A typical present perfect clause thus consists of the subject, the auxiliary have/has,
and the past participle (third form) of the main verb. Examples:

• I have eaten some food.


• You have gone to school.


• He has already arrived in Catalonia.


• He has had child after child... ( The Mask of Anarchy , Percy Shelley)


• Lovely tales that we have heard or read... ( Endymion (poem) , John Keats)

Early Modern English used both to have and to be as perfect auxiliaries.
Examples of the second can be found in older texts:

• Madam, the Lady Valeria is come to visit you. (The Tragedy of Coriolanus , Shakespeare)


• Vext the dim sea: I am become a name... ( Ulysses , Tennyson)


• Pillars are fallen at thy feet... (Marius amid the Ruins of Carthage, Lydia Maria Child)


• I am come in sorrow. (Lord Jim, Conrad)

http://en.wikipedia.org/wiki/Present_perfect