BCGSuite for MFC
void CBCGPDialog::SetControlInfoTip ( UINT  nCtrlID,
LPCTSTR  lpszInfoTip,
DWORD  dwVertAlign = DT_TOP,
BOOL  bRedrawInfoTip = FALSE,
CBCGPControlInfoTip::BCGPControlInfoTipStyle  style = CBCGPControlInfoTip::BCGPINFOTIP_Info,
BOOL  bIsClickable = FALSE,
const CPoint &  ptOffset = CPoint(0, 0) 

Adds an information tip to the dialog child control specified by control ID.

nCtrlIDIdentifier for the control.
lpszInfoTipThe information tip text. Set this parameter to NULL to remove the infotip previously added to the control.
dwVertAlignThe vertical align. Can be DT_TOP, DT_VCENTER or DT_BOTTOM.
bRedrawInfoTipSpecifies whether an information tip should be redrawn.
styleSpecifies the information tip style.
bIsClickableSpecifies whither the information tip clickable or not.
ptOffsetSpecifies info tip screen offset from the default position.

Each control located on the dialog can be associated with right-side located small info mark. When user hovers the mouse cursor over this info mark, the screen tip with control description will appear. If bIsClickable is TRUE, the framework sends BCGM_ONCLICKINFOTIP registered message to the dialog when user clicks the info tip.