Yes.
How you do it depends on where you live, the type of Pronto and how much you want to spend.
In N. America, X-10's IR543 receives IR and sends PLC commands to the powerline. There are CCF codes in the Files area for this. The IR543 is limited to a single X-10 housecode.
The IR543AH is an IR543 that has been modified by a third party (Laser in the UK). It will handle all 16 housecodes and can also do preset dim and extended codes. You'll need CodeGen to generate the codes. The IR543AH is available from multiple sources - do a Google search.
Outside of N. America, X-10 sells the IR7243 which can do all housecodes (but not preset dims nor extended codes). I think you need CodeGen to create the IR codes as X-10 merely copied the protocol that was developed by Laser for the IR543AH.
Outside of N. America, Prontos (and clones) that send RF can control X-10 RF devices directly as both use 433.92MHz.
If you want to control X-10 using IR but do not have line-of-sight to the IR543/IR543AH/IR7243, the Powermid transmitter from X-10 (others make similar devices) receives IR and relays it as RF to the Powermid receiver which repeats it as IR. Put the receiver where it has line-of-sight to the IR543/IR543AH/IR7243.
CodeGen is available at...
[Link: mbx-usa.com]