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 :
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