Hello !
UI is the WEB technology like WebDyn Pro. To use it you should be an abap developer to create an applications with WEB interface (for smartphones for example) and using SAP system as database. For exapmle: you have SAP ERP system and you want to organize the Online Shop in internet. Web users will see you Online Shop just like a usual web page in internet, but it is directly connected to you ERP, they can get an information about remaining stocks online and so on. Also it's simple to create an interface for IPAD, iphones on WebUI.
If you just want you use SAP via web browser just use ITS.
If services is activated in SICF transaction you can you URL:
for example http://hostname:8000/sap/bc/gui/sap/its/webgui
