I tried to install php5 via tar package in my debian etch system(Apache-2 is already installed by default)
while executing #./configure --with suffix=/usr/local/php --with-mysql=/usr/local/mysql, it reported that xml config file is not there and check the libxml2 file

I have downloaded libxml2 file and installed via #dpkg -i libxml2...
but the same message shows. What should I do to install php on my system?

Erhm.. issue `apt-get install php5` ?

while executing the command
#apt-get install libxml2_2.6.27.dfsg-1_i386

Reading package lists...........Done
Building dependency tree.........Done

couldn't find package libxml2_2.6.27.dfsg-1_i386


I installed the libxml2 via dpkg and i think it installed correctly (On the synaptic package manager, it seems libxml2 installed)

But while executing the command

#./configure --prefix='/usr/local/php'

................
.............

checking whether to enable LIBXML support ..........yes
checking libxml2 install dir ...............no
checking for xml2_conf path...........
configure error:xml2_config not found please check your
libxml2 installation

I guess you don't wish to take my advice to use apt-get to install php5 directly. And the error you got from apt-get is very normal, read the manual page of apt-get and perhaps you'll see why.

I have installed libxml2 via the tar package without no problem.

I have also installed php5

Ok reverse, I shall try the other way also, via apt-get install