Cleartype is not turned on by default over Remote Desktop Protocol (RDP). Thus, if you connect to a computer using Remote Desktop Connection (RDC) you will notice aliased fonts, quite ugly in my opinion without Cleartype enabled.
If you are connecting to a Vista or Windows 7 computer, enable Experience → Font smoothing in the RDC dialog.
If you are connecting to a Windows XP computer, a bit more work is needed. Apply the following Registry entries on that computer:
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations] "AllowFontAntiAlias"=dword:00000001 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp] "AllowFontAntiAlias"=dword:00000001
Or just place these lines in a file named CleartypeOnRDP.reg file and execute it.