I just performed an upgrade from 1.5 beta to klok 2.0 release and there IS a way to easily import all your old stuff.

1. First install Klok2, I backed up my Klok.dat(On Vista/7 located in C:Users{UserName}AppDataRoamingKlok.AF6B2973D903BFAE0589C27890FE0146C233490A.1Local Store replace {UserName} with your current user’s name) for 1.5 beta but this was NOT needed as Klok 1.5 beta and Klok2 can run side by side.

2.Once Klok2 is installed back up your Klok.dat if you haven’t already.(same location as above; just to be safe.)
Then Open Klok2 and Click the down arrow on Tools and select “Import Klok 1.x data“
[attachment=0:124eccrx]Klok_Import.JPG[/attachment:124eccrx]
3. It will open a file explorer (On Vista/7) go to C:Users{UserName}AppDataRoamingKlok.AF6B2973D903BFAE0589C27890FE0146C233490A.1Local Store replace {UserName} with your current user’s name.
Select your klok.dat file and click OPEN.

4. Next it will confirm the import(According to the text it may take several minutes depending on the number of projects and time entries that you have, also I assume it depends on the speed of your computer as well.)
I had 1006 items(91 projects and 915 time entries)on my fairly fast work machine it took less than 15 seconds.
Clock Continue with Import.

If everything went as planed you should have time entries and projects rolled over to the Klok2.

Hope that helps.