I can not install PHP in edgy. I install the packages php5 and libapache2-mod-php5 but the php din't in install in apache.

By default if you install apache2, php5 and libapache2-mod-php5, it should have worked. If during the install something goes wrong, you should report the errors cause it's pretty stable.
Try to reinstall:
Check that /etc/apache2 doesn't exist anymore otherwise delete it

When I type a2enmod php5 the out put is this module does not exist

Did you reinstall it and then tried the a2enmod?
If not, try to do it.
You're not the first person who encounters this problem. Here I had no problems with the procedure that I gave.

I did: apt-get --purge remove apache2 php5 libapache2-mod-php5
and I delete de file apache2 in /etc/apache2
Now, when I try install apache the file /etc/apache2 and this contents don't appears no more? How can I solve this?

Sorry I forgot one package which I thought would be removed by removing apache2.
So redo this (to be sure)
apt-get --purge remove apache2 php5 libapache2-mod-php5

Then
Do this:
apt-get --purge remove apache2.2-common
apt-get --purge remove apache2-common

These are the packages that include /etc/apache2. Its either apache2.2-common or apache2-common so one of the above command will tell you that the package don't exist (on my debian apache2-common doesn't exist anymore but I don't know for your ubuntu)


Check nothing belonging to apache2 is still present:
dpkg -l *apache2* | grep ^ii
If you still have result, remove the packages (by using --purge remove like above)


And then reinstall apache2


Hope this time I haven't forgotten one.
Sorry again

This is directly from the "The perfect Setup Guide"

Next we install PHP5:

apt-get install autoconf automake1.4 autotools-dev libapache2-mod-php5 php5 php5-common php5-curl php5-dev php5-gd php-pear php5-ldap php5-mhash php5-mysql php5-mysqli php5-snmp php5-sqlite php5-xmlrpc php5-xsl php5-imap php5-mcrypt php5-pspell