How to check details of the rpm pacakge which is yet not installed?

Pass "-qpil" to rpm command. As an example :

#rpm -qpil tftp-0.49-7.el6.x86_64.rpm
Name : tftp Relocations: (not relocatable)
Version : 0.49 Vendor: Red Hat, Inc.
Release : 7.el6 Build Date: Mon 18 Jul 2011 03:10:21 PM EDT
Install Date: (not installed) Build Host: x86-002.build.bos.redhat.com
Group : Applications/Internet Source RPM: tftp-0.49-7.el6.src.rpm
Size : 46554 License: BSD
Signature : (none)
Packager : Red Hat, Inc.
URL : http://www.kernel.org/pub/software/network/tftp/
Summary : The client for the Trivial File Transfer Protocol (TFTP)
Description :
The Trivial File Transfer Protocol (TFTP) is normally used only for
booting diskless workstations. The tftp package provides the user
interface for TFTP, which allows users to transfer files to and from a
remote machine. This program and TFTP provide very little security,
and should not be enabled unless it is expressly needed.
/usr/bin/tftp
/usr/share/doc/tftp-0.49
/usr/share/doc/tftp-0.49/CHANGES
/usr/share/doc/tftp-0.49/README
/usr/share/doc/tftp-0.49/README.security
/usr/share/doc/tftp-0.49/README.security.tftpboot
/usr/share/man/man1/tftp.1.gz


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To check details of installed package :

#rpm -qi tftp-0.49-7.el6.x86_64
Name : tftp Relocations: (not relocatable)
Version : 0.49 Vendor: Red Hat, Inc.
Release : 7.el6 Build Date: Mon 18 Jul 2011 03:10:21 PM EDT
Install Date: Fri 19 Aug 2011 06:02:18 PM EDT Build Host: x86-002.build.bos.redhat.com
Group : Applications/Internet Source RPM: tftp-0.49-7.el6.src.rpm
Size : 46554 License: BSD
Signature : (none)
Packager : Red Hat, Inc.
URL : http://www.kernel.org/pub/software/network/tftp/
Summary : The client for the Trivial File Transfer Protocol (TFTP)
Description :
The Trivial File Transfer Protocol (TFTP) is normally used only for
booting diskless workstations. The tftp package provides the user
interface for TFTP, which allows users to transfer files to and from a
remote machine. This program and TFTP provide very little security,
and should not be enabled unless it is expressly needed

Show dependencies of a RPM package :

#rpm -qp -requires .rpm