Yes - if you use the "Professional", "Enterprise" or "Unlimited" version of Salesforce you can create a checkbox that will allow you to select the tasks that sync with vWork to create jobs in vWork. Instructions for adding a custom checkbox within Salesforce to enable this are given below.

If you use "Contact Manager" or "Group" versions of Salesforce, you don't have access to the functionality to add custom checkboxes to salesforce.  This means that all of your tasks sync with vWork and create jobs. 

Add a custom checkbox within Salesforce

To add a custom checkbox within Salesforce:

1. Log into your Salesforce CRM account.
2. Find your username in the top right corner of Salesforce. To the right of your username click Setup.
3. In the left-hand menu, find the Build menu.
4. Click Customize,
5. Click Customize your Activities,
6. Click Add a Custom Field to activities.
7. Select Checkbox and click Next.
8. In the Field Label enter vWorkApp Link. (This name is required).
   The Field Name is automatically entered.
9. Cut and paste the following copy into the Help Text box:
   "Tick this box if you wish to create a job in vWork for this task."
10. Click Next.
11. If you have multiple profiles make sure the checkbox is available to your preferred profiles.
12. When you are satisfied that the checkbox is available to your profile(s) click Next. 
13. Make sure that the Event Layout and Task Layout checkboxes are selected.
14. Click Save.

That's all there is to it. When you create a new task you will see a checkbox called vWorkApp Link. Add a checkmark to this box when you want the task to create a job in vWork.