Connect to another clients ?
 

Does LimeWare can connect to another (for example - BearShare) clients ?

yes

see http://www.limewire.com/english/content/uastats.shtml for the list of vendors currently connected to the gnutella network.

Yes, but in my connection window I see only LimeWare cllients ...

that's not surprising, since it is the most widely used gnutella client and its open source code is widely used by many other vendors like etomi, 360Share, and Acquisition (even if they don't give much back in return)

BearShare leafs only connect to BearShare ultrapeers, so you'll only see BearShare Ultrapeers connecting to LimeWire Ultrapeers. I rarely see more than a couple of BearShares each session

btw--if you are running as an Ultrapeer, LW prevents ALL its connections being taken up by LW's. 2 of the 32 slots are always reserved for non-LW vendors, though more are allowed to connect under the usual first-come first-served pattern.