Creating a Web Part Page:
From the main site collection, click the Site Actions button and choose Create from the dropdown
Under Web Pages on the next screen, click Webpart Page.
Give the Web Part Page a name, choosing desired layout and choose where you would like it saved. Then click Create.
After you click Create, the page will open from the lib. Where you have saved it.
You can start editing the page from here by adding Web Parts of your choice and can edit the page later by going to the doc. lib where you have saved it.
Setting Web Part page as your SharePoint Home page
This can easily be done is SharePoint Designer. If you have not installed SharePoint designer as a part of Office 2007 Enterprise, I highly recommend it. If you do not have Office 2007 Enterprise edition, MS offers a free 30 day trial of SharePoint Designer to test out as well.
In SharePoint Designer, open the site where you saved the web part page you created. In my case it is located in my personal site. When I created the web part page, I chose to save in Documents. Hit the + and expand the Documents folder to find you Web Part page.
Drag the page out of the folder and below the default.aspx page.
This takes it out of the place is SharePoint where is it was stored to prevent other people from making changes. Now it is associated with the site only.
Right click on your web part page and select Set as Home Page.
Click OK to the message.
Click OK to the next message if it appears.
This will be renaming your old default page as default-old.aspx and will name the Web Part page as default.aspx page.
You can also preview this page in your browser. Now you can see that your site has the web part page you created earlier, and you are able to edit the page accordingly. SharePoint Designer is incredibly powerful and you can do things much faster here than in SharePoint itself. Try it out for yourself.
If you have any queries/questions regarding the above mentioned information then please let me know. Thank you.