Disappointingly, the CyanogenMod team have failed to release a named snapshot of CyanogenMod 9 for the HP TouchPad since the Alpha 2 release some 4 months ago. Whilst this gives the impression that development of CM9 for the TouchPad has been abandoned, the reality is that there are actually builds with small incremental changes appearing on a regular basis.
After hanging on for Alpha 2 as long as I could, I caved in and decided to try out these "nightlies". However, I was keen to avoid the messy host PC/USB/novacom method that I'd been using for the named releases. Luckily, this is where the very handy GooManager Beta comes in - once you've got any CM9 release on your HP TouchPad, GooManager takes over and lets you easily upgrade to any recent nightly and also keep your Google Apps ("GApps") release up to date.
All you need to do is run GooManager, select "Browse compatible ROMs", then the first "nightly" category (/cm/tenderloin/nightly) and finally pick the first (most recent) nightly - e.g. cm-9-20120622-NIGHTLY-tenderloin.zip. Select "Begin download" and once the download starts, you can tap around the task bar clock area and bring up the notifications list, which includes a download progress bar.
When the download completes, go back to the first screen and select "Flash ROMs". Making sure that just the one download is ticked, then select "Order & flash selected". Tick on the first option - "Wipe cache/dalvik cache partition" - and if you haven't made a backup yet, tick on "Create backup" (you will be asked for a backup name - I used CM9A2 for the last named release). Don't tick "Wipe data" because I suspect it deletes all your apps! Finally, select Flash and confirm the flash process by selecting Yes.
The TouchPad will reboot and then boot into a temporary loader that installs the nightly you downloaded. Don't worry if it moans about a missing md5 file (GooManager doesn't seem to bother downloading it). The TouchPad will reboot after the install, but this time will go into the nightly release, which now includes a fancy "friendly vs. evil" CM9 boot animation. CM9 will "optimise" all your apps and then display the CM9 home screen as usual - all your apps and data should be intact. Have fun with your nightlies - you know it makes sense :-)