What i do is to include my customzation in one or more Features, and deploy  those features and other related customization using a Solution.



Features and Solutions is actually defined using Xml files using different CAML schemas



Here is a list of CAML schemas



http://msdn2.microsoft.com/en-us/library/ms462365.aspx



The ones that would be interested in are probably:



Feature

http://msdn2.microsoft.com/en-us/library/ms414322.aspx



Solution

http://msdn2.microsoft.com/en-us/library/ms442108.aspx



Site

http://msdn2.microsoft.com/en-us/library/aa544502.aspx



Once you have defined your Feature(s) and Solution, you must create a ddf file containing references to all files refrenced by your feature(s) and solution in order to generate a .wsp (a cab file with another extension) file wich is the actual installable.



I have included a very very simple feature for you to build on, the only thing the feature does is to provision a single file to the style library:



Feature.xml

<!-- _lcid="1033" _version="12.0.4407" _dal="1" -->
<!-- _LocalBinding -->
<Feature  Id="5b3ec5b8-e35a-4cef-ac21-3f0156bc6c00"
          Title="SimpleFeature"
          Description="A feature that provisions a single file"
          Version="1.0.0.0"
          Scope="Site"
          Hidden="False"
          DefaultResourceFile="core"
          Creator="You"
          ActivateOnDefault="True"
          AlwaysForceInstall="True"
          xmlns="http://schemas.microsoft.com/sharepoint/">
  <ElementManifests>
    <ElementManifest Location="ProvisionedFiles.xml"/>
  </ElementManifests>
</Feature>



ProvisionedFiles.xml



<?xml version="1.0" encoding="utf-8"?>
<!-- _lcid="1033" _version="12.0.4518" _dal="1" -->
<!-- _LocalBinding -->
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Module Name="Yourfile" Url="Style Library" Path="" RootWebOnly="TRUE">
    <File Url="yourfile.txt" Type="GhostableInLibrary" />
  </Module>
</Elements>

Manifest.xml (Solution)



<?xml version="1.0" encoding="utf-8" ?>
<Solution SolutionId="b3f346ba-5d7f-43fb-a6d4-78726db5d573" xmlns="http://schemas.microsoft.com/sharepoint/" DeploymentServerType="WebFrontEnd">
  <Resources>
    <Resource Location="SimpleFeature\Feature.xml"/>
    <Resource Location="SimpleFeature\ProvisionedFiles.xml"/>
    <Resource Location="SimpleFeature\yourfile.txt"/>
 </Resources>
</Solution>



Solution.ddf



;*** Sample Source Code MakeCAB Directive file example
;
.OPTION EXPLICIT
.Set CabinetNameTemplate=SimpleSolution.wsp
.set DiskDirectoryTemplate=CDROM
.Set CompressionType=MSZIP
.Set UniqueFiles=off
.Set Cabinet=on
.Set DiskDirectory1=Packages
.Set MaxDiskSize=14576640
manifest.xml
.Set DestinationDir=SimpleFeature
SimpleFeature\Feature.xml
SimpleFeature\ProvisionedFiles.xml
SimpleFeature\yourfile.txt