Salesforce CRM provides two tools for data migration—the Import Wizard and the Apex Data Loader.

The Import Wizard

is designed for less-technical users and smaller, simple imports of up to 50,000 records. It takes you through the process step by step and displays error messages to alert you to potential record duplications (“dupes”). For more information, go to Help & Training | Importing Data | Using the Import Wizards.

Use the Apex Data Loader

for complex imports of any size. It’s for technical users only. You’ll need access to the API to use this tool, which is included with Enterprise and Unlimited Edition. If you have another edition, you can purchase the API separately by contacting your account executive. The Data Loader doesn’t display error messages to alert you to potential problems. However, this tool includes several features that help make large data imports easier, such as being able to save your mappings. For more information, go to Help & Training | Data Loader.

The table below summarizes the difference between the two tools. The instructions in the remaining steps refer to the Import Wizard.

1. Page Break
While generating PDF template from Visualforce, if you want to give the page break ,below code snippet is very useful.
You can use the page break style properties to control where the browser will insert a page break. The Force.com PDF content converter will carry that over to the PDF.

<apex:page renderas="pdf">
<div style="page-break-after:always;">
This is page one
</div>
</apex:page>

2. Page layout and Page number
The following snippet shows you have to switch the PDF page layout to landscape and add page numbers to your Visualforce page. Use the below code in CSS of Visualforce page.

@page {
/* Landscape orientation */
size:landscape;
/* Put page numbers in the top right corner of each page in the pdf document. */
@top-right
{
content: “Page ” counter(page);
}
}

Source : Kyle Roche / Pragya Kumari

Problem Statement
The Apex Developers Guide says there is a maximum of 10 sendEmail methods per transaction (page 310). Is this counted by individual message sent, or by line of code executed? Example: What if you have 11 messages in a Messaging.SingleEmailMessage array and call the sendEmail method once using this array? (Each message in the array has slightly different content, which is why I’m not using mass email.)

Solution (Ack : Anand)
The limit is on the number of times “SendEmail(…)” method is called not the number of SingleEmailMessage int he Array. So theoretically you can send 10 x 1000 emails (assuming you have an array of 1000 SingleEmailMessage for every sendEmail call) .