Following up to this post and this post, here’s quick instructions on how to actually get the proper pdo_oci package on Debian Squeeze.
First, install the pdo extension as described in the second link above.
Then, begin the same procedure for pdo_oci, but stop right after the command dh-make-pecl
Now comes the magic. Open the file debian/rules in the newly created dir (php-pdo-oci-1.0.1).
Change the constant PECL_PKG_NAME=pdo-oci to PECL_PKG_NAME=pdo_oci
Now look for the block configure-stamp-v4 configure-stamp-v5:
There, right after the line that says $(PHPIZE)$*; \
insert these lines:
sed -e 's/prefix\/include\/php\/ext/prefix\/include\/php5\/ext/' configure > /tmp/pdo_oci-configure; \
cp /tmp/pdo_oci-configure ./configure; \
Save the file and proceed as explained in the referred post. That should do it! 
