perseverance is the ONLY answer, everytime she comes to your bed stop her before she gets in if you can. A quick cuddle and back to her own bed. DONT linger, just put her down say goodnight and leave.  Done enough times the message will get thru quickly.  Shouldn't take more than 2 or 3 nights to take effect.

Also you might need to consider where the new baby will sleep, if in your room then this must be explained to your elder child sooner rather than later as this can couse other similar problems.

Perseverence is the key...  Just keep putting him back into bed..  We all know it's hard int he middle of the night, but it does work.  And I'm sorry, but it's the only way I know of..

Good luck..  And remember...  If it's a normal routine it only takes a little while to re-establish..  And it's definitely better done now than when the baby arrives..

Best wishes..  and good luck for the birth.

We had the same problem with our then 2 year old (she's now 3).  We found that being persistant in putting her back into her own bed helped, using a nightlight that turns off after about an hour, and even laying on her bed with her until she went back to sleep. We also used to let her go to sleep on the couch (after she woke up) and then put her back into her bed when we went to bed.

Clearly, our kids like being sandwhiched between 2 hot water bottles, but it would be nice if they kept their hands and feet to themselves! LOL.  Bruised kidneys isn't fun!