There is no problem about ur query. Keep extra care when installing the new version in a different folder to the old version, so that u can keep the old versions also.
In Outlook 2010, u have to set mail settings to import mail settings like :
1. Open Outlook > File > Open > Import
2. Choose an action to perform box, click Import Internet Mail Account Settings, and then click Next
3. Select e-mail client to import box, click Microsoft Outlook Express or Microsoft Windows Mail, or Microsoft Windows Mail, and then click Next
Remember, make sure that the name that is displayed is the name that u want to use and then click Next.
4. Make sure that the incoming and outgoing mail servers are correct, and then click Next.
For more info click this link :
http://itknowledgeexchange.techtarget.com/itanswers/i-installed-outlook-2010-on-outlook-2000-but-i-forgot-to-export-my-pst-files-how-can-i-retrieve-the-2000-pst-file/
And for Microsoft recommendation please link here
http://support.microsoft.com/kb/291602
Also keep in mind the newer version of Outlook is going to need more RAM to run. You may want to check if you have sufficient resources on your existing system and buy more RAM if needed.