I have tried to upload my database using the Sync Framework Power Pack for SQL Azure using SQL Server 2008 Express but only with limited success. My problem is that it creates the structure of my azure database but not the data. Upon further research I found out that the Sync wizard creates a job that can be run latter to do the actual upload of the data. The problem is that Express doesn't have agent to run the job at least not through the SSMS gui. I did read somewhere that your could run this job through a command line prompt but I don't know where this job is or how to run it. FYI I'm a newbie to SQL Server 2008 and Express
Hopefully this thread will give you some background on the issue. Unfortunately we do not support Express with this CTP (but are hoping to for the next release). Ultimately you would need to temporarily install something with SQL Agent capabilities on that machine to get the command line.