Sitefinity doesn't support using content from Sharepoint out-of-the-box. We think it would be easy to create a user control that takes the content from Sharepoint. Once you have this data, you have two options:
1) Display the information directly
2) Store the information to the Sitefinity database for later use, using the Sitefinity API.
Sitefinity supports sharing of information between several web sites out-of-the-box. If you choose the second option, then every piece of information that you take from Sharepoint could be shared between several sites, but stored in a single database.
I hope you find this answer helpful. Let us know if we could assist you with anything else.
the Telerik team