Question

I have made a small application in android and I want to publish it on market.

So first of all how to export final APK from eclipse and
second what are the parameters to set in AndroidManifest file?

Please, help me.

Answer 1

1) Extracting signed package

A quote from here:

Compiling and signing with Eclipse ADT
When using Eclipse with ADT, you can
use the Export Wizard to export a
signed .apk (and even create a new
keystore, if necessary). The Export
Wizard performs all the interaction
with the Keytool and Jarsigner for
you, which allows you to perform
signing via a graphical interface
instead of the command-line. Because
the Export Wizard uses both Keytool
and Jarsigner, you should ensure that
they are accessible on your computer,
as described above in the Basic Setup
for Signing.

To create a signed .apk, right-click
the project in the Package Explorer
and select Android Tools > Export
Signed Application Package.
(Alternatively, open your
AndroidManifest.xml file in Eclipse,
open the Overview tab, and click Use
the Export Wizard.) The window that
appears will display any errors found
while attempting to export your
application. If no errors are found,
continue with the Export Wizard, which
will guide you through the process of
signing your application, including
steps for selecting the private key
with which to sign the .apk, or
creating a new keystore and private
key.

When you complete the Export Wizard,
you’ll have a signed .apk that’s ready
for distribution.

2) Manifest
There are a lot of params in manifest file. The main ones you need is:
Parameters of manifest tag:

package="com.yourcompany.yourapppackage"

is the package name of your project. I assume you already have it.

android:versionCode="4" android:versionName="1.0.3"

These two describes the code and name of the version of your software. version code should be always an integer, and version name can be any string you like. Don’t forget to increase your version code, when uploading an update.

Nested tag <uses-sdk android:minSdkVersion="3" />
is a tag, which specifies the minimum api level your application uses.

Nested tags <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> are necessary only if you need some permissions for application.

Read more about manifest file here.