I played at Party and started making this stuff for myself - the Party Monster script was starting to fall apart. A few mates used it, then it was free for a while, then I just got into it more. Party is easy to make Software for, but the positional stuff is possible anywhere, it's a confusing bit of code, took a lot of mucking around to get right.
Full Tilt was easy to code for and I had my own script for playing there, bet pot stuff and a planner for SNG's, never released that though.
I think you'll find that this will be built into the client soon enough, Pokerstars has a beta already, no?
But I don't think I'd write another program as I'm just cruisin along these days - and brewing beer has become my favorite pastime.