As you are probably aware, Salesforce to Salesforce now supports sharing Product Catalog and Opportunity Products with connections. Additionally, customers can automate this process using the API feature and share the same product with multiple connections (e.g. reseller and distributor) using the 1:Many feature. Sharing opportunity products is a little more involved compared to other objects. Below is a checklist that you should be aware of to successfully share Products on opportunities:

1) Parent Opportunity must be shared with the connections
2) Product Catalog must be shared with the connections (use the Products list view feature on the Products tab to select Products Catalogs to share)
3) Product Catalog must be active and also be in the price book of the target opportunity
4) Source's Opportunity currency and target's Opportunity currency should match and the product in the target's opportunity price list must also have the currency available and active
5) If the target product has schedules then Quantity and Sales Price are only inserted but never updated
6) Opportunity Product can be shared when sharing the opportunity or using the 'Manage Connections' link on the Sent Connection Name column on the Products related list on the Opportunity

If you have any questions, reach out to product management at: s2s@salesforce.com