Magento has default translations available for download. You can use them as your starting point. Visit this page http://www.magentocommerce.com/translations
for more info.
To translate the text to your native language you should edit *.csv files.
(Please note that all our extension's csv file names for translation start with "Plumrocket_")
On your development server go to "/app/locale/en_US/". This folder should have all the texts in English. You have a choice to just translate all the texts in it or to copy it and create a separate folder for your language here - "/app/locale/"
In order to translate, just open one of *.csv files and you will see something similar to the following:
"Backup file not found","Backup file not found"
"Backup file path was not specified.","Backup file path was not specified."
If you want to change text "Backups" to your language you should do the following:
"Backups", "TEXT IN YOUR LANGUAGE"
Save file and clear magento cache (System->Cache Management->Flush cache)
To translate categories:
1. From the Admin menu, select Catalog > Manage Categories.
2. Set "Choose Store View" to the target language for the translation.
3. In the category tree on the left, select a category or subcategory to be translated. Then, do the following:
4. Clear the "Use Default Value" checkbox after the category to be translated.
5. Insert the translated content for the category.
6. Once completed, click the "Save Category" button and clear magento cache.
To translate Pages/Static Blocks:
1. From the Admin menu, select CMS > Pages
2. Click the "Add New Page" button to create a new page for the translated content.
3. In the Page Information section, set "Store View" to view where the translated page will be available.
4. Insert the translated content and edit as you need. Make sure to translate the URL Key and any meta data associated with the page.
5. Once completed, click the "Save Page" button. Clear magento cache.
If something is not clear, please feel free to ask.