mobical.net offers a SyncML solution. MightyPhone is more supported and not free, but they offer plugins and such for Outlook users. it can perform a SyncML sync too, and there are betas of SyncML applications for BlackBerry devices in the Sync4J source tree IIRC.
Sempai, have you tried to get Mobical to work, and if so which SyncML client did you use? I tried but couldn't get it to work. I didnt see any blackberries that were supported and couldn't get the manual setup to work. I sent a feedback asking about the Nextel 7520 and the developer got back right away. I've quoted his response here:
my name is David Johansson. I am the product manager for Mobical.
Mobical.net is a solution based on SyncML. To the best of my knowledge, your 7520 Blackberry doesn't support SyncML out-of-the-box, but instead relies on a proprietary RIM/Blackberry protocol for synchronizing. Our manual settings instructions refer to a special sync profile which should be part of the SyncML application, and so you cannot use it as described.
To enable SyncML in your Blackberry, you should first download and install a 3rd party SyncML client. In the future, such clients will be available for purchase directly on Mobical.net, but we have not yet had the time to certify them. I would recommend pretty much any commercial grade client except the Sync4j, which has a non-standard data format. Perhaps you could ask in the BlackBerry Forums for help and experiences from other users?